summaryrefslogtreecommitdiffstats
path: root/tools/kvm/kvm_stat/kvm_stat
blob: 581278c5848877ea1a90cfdbf8045afd23298c0c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
#!/usr/bin/python
#
# top-like utility for displaying kvm statistics
#
# Copyright 2006-2008 Qumranet Technologies
# Copyright 2008-2011 Red Hat, Inc.
#
# Authors:
#  Avi Kivity <avi@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.  See
# the COPYING file in the top-level directory.
"""The kvm_stat module outputs statistics about running KVM VMs

Three different ways of output formatting are available:
- as a top-like text ui
- in a key -> value format
- in an all keys, all values format

The data is sampled from the KVM's debugfs entries and its perf events.
"""

import curses
import sys
import os
import time
import optparse
import ctypes
import fcntl
import resource
import struct
import re
from collections import defaultdict
from time import sleep

VMX_EXIT_REASONS = {
    'EXCEPTION_NMI':        0,
    'EXTERNAL_INTERRUPT':   1,
    'TRIPLE_FAULT':         2,
    'PENDING_INTERRUPT':    7,
    'NMI_WINDOW':           8,
    'TASK_SWITCH':          9,
    'CPUID':                10,
    'HLT':                  12,
    'INVLPG':               14,
    'RDPMC':                15,
    'RDTSC':                16,
    'VMCALL':               18,
    'VMCLEAR':              19,
    'VMLAUNCH':             20,
    'VMPTRLD':              21,
    'VMPTRST':              22,
    'VMREAD':               23,
    'VMRESUME':             24,
    'VMWRITE':              25,
    'VMOFF':                26,
    'VMON':                 27,
    'CR_ACCESS':            28,
    'DR_ACCESS':            29,
    'IO_INSTRUCTION':       30,
    'MSR_READ':             31,
    'MSR_WRITE':            32,
    'INVALID_STATE':        33,
    'MWAIT_INSTRUCTION':    36,
    'MONITOR_INSTRUCTION':  39,
    'PAUSE_INSTRUCTION':    40,
    'MCE_DURING_VMENTRY':   41,
    'TPR_BELOW_THRESHOLD':  43,
    'APIC_ACCESS':          44,
    'EPT_VIOLATION':        48,
    'EPT_MISCONFIG':        49,
    'WBINVD':               54,
    'XSETBV':               55,
    'APIC_WRITE':           56,
    'INVPCID':              58,
}

SVM_EXIT_REASONS = {
    'READ_CR0':       0x000,
    'READ_CR3':       0x003,
    'READ_CR4':       0x004,
    'READ_CR8':       0x008,
    'WRITE_CR0':      0x010,
    'WRITE_CR3':      0x013,
    'WRITE_CR4':      0x014,
    'WRITE_CR8':      0x018,
    'READ_DR0':       0x020,
    'READ_DR1':       0x021,
    'READ_DR2':       0x022,
    'READ_DR3':       0x023,
    'READ_DR4':       0x024,
    'READ_DR5':       0x025,
    'READ_DR6':       0x026,
    'READ_DR7':       0x027,
    'WRITE_DR0':      0x030,
    'WRITE_DR1':      0x031,
    'WRITE_DR2':      0x032,
    'WRITE_DR3':      0x033,
    'WRITE_DR4':      0x034,
    'WRITE_DR5':      0x035,
    'WRITE_DR6':      0x036,
    'WRITE_DR7':      0x037,
    'EXCP_BASE':      0x040,
    'INTR':           0x060,
    'NMI':            0x061,
    'SMI':            0x062,
    'INIT':           0x063,
    'VINTR':          0x064,
    'CR0_SEL_WRITE':  0x065,
    'IDTR_READ':      0x066,
    'GDTR_READ':      0x067,
    'LDTR_READ':      0x068,
    'TR_READ':        0x069,
    'IDTR_WRITE':     0x06a,
    'GDTR_WRITE':     0x06b,
    'LDTR_WRITE':     0x06c,
    'TR_WRITE':       0x06d,
    'RDTSC':          0x06e,
    'RDPMC':          0x06f,
    'PUSHF':          0x070,
    'POPF':           0x071,
    'CPUID':          0x072,
    'RSM':            0x073,
    'IRET':           0x074,
    'SWINT':          0x075,
    'INVD':           0x076,
    'PAUSE':          0x077,
    'HLT':            0x078,
    'INVLPG':         0x079,
    'INVLPGA':        0x07a,
    'IOIO':           0x07b,
    'MSR':            0x07c,
    'TASK_SWITCH':    0x07d,
    'FERR_FREEZE':    0x07e,
    'SHUTDOWN':       0x07f,
    'VMRUN':          0x080,
    'VMMCALL':        0x081,
    'VMLOAD':         0x082,
    'VMSAVE':         0x083,
    'STGI':           0x084,
    'CLGI':           0x085,
    'SKINIT':         0x086,
    'RDTSCP':         0x087,
    'ICEBP':          0x088,
    'WBINVD':         0x089,
    'MONITOR':        0x08a,
    'MWAIT':          0x08b,
    'MWAIT_COND':     0x08c,
    'XSETBV':         0x08d,
    'NPF':            0x400,
}

# EC definition of HSR (from arch/arm64/include/asm/kvm_arm.h)
AARCH64_EXIT_REASONS = {
    'UNKNOWN':      0x00,
    'WFI':          0x01,
    'CP15_32':      0x03,
    'CP15_64':      0x04,
    'CP14_MR':      0x05,
    'CP14_LS':      0x06,
    'FP_ASIMD':     0x07,
    'CP10_ID':      0x08,
    'CP14_64':      0x0C,
    'ILL_ISS':      0x0E,
    'SVC32':        0x11,
    'HVC32':        0x12,
    'SMC32':        0x13,
    'SVC64':        0x15,
    'HVC64':        0x16,
    'SMC64':        0x17,
    'SYS64':        0x18,
    'IABT':         0x20,
    'IABT_HYP':     0x21,
    'PC_ALIGN':     0x22,
    'DABT':         0x24,
    'DABT_HYP':     0x25,
    'SP_ALIGN':     0x26,
    'FP_EXC32':     0x28,
    'FP_EXC64':     0x2C,
    'SERROR':       0x2F,
    'BREAKPT':      0x30,
    'BREAKPT_HYP':  0x31,
    'SOFTSTP':      0x32,
    'SOFTSTP_HYP':  0x33,
    'WATCHPT':      0x34,
    'WATCHPT_HYP':  0x35,
    'BKPT32':       0x38,
    'VECTOR32':     0x3A,
    'BRK64':        0x3C,
}

# From include/uapi/linux/kvm.h, KVM_EXIT_xxx
USERSPACE_EXIT_REASONS = {
    'UNKNOWN':          0,
    'EXCEPTION':        1,
    'IO':               2,
    'HYPERCALL':        3,
    'DEBUG':            4,
    'HLT':              5,
    'MMIO':             6,
    'IRQ_WINDOW_OPEN':  7,
    'SHUTDOWN':         8,
    'FAIL_ENTRY':       9,
    'INTR':             10,
    'SET_TPR':          11,
    'TPR_ACCESS':       12,
    'S390_SIEIC':       13,
    'S390_RESET':       14,
    'DCR':              15,
    'NMI':              16,
    'INTERNAL_ERROR':   17,
    'OSI':              18,
    'PAPR_HCALL':       19,
    'S390_UCONTROL':    20,
    'WATCHDOG':         21,
    'S390_TSCH':        22,
    'EPR':              23,
    'SYSTEM_EVENT':     24,
}

IOCTL_NUMBERS = {
    'SET_FILTER':  0x40082406,
    'ENABLE':      0x00002400,
    'DISABLE':     0x00002401,
    'RESET':       0x00002403,
}

class Arch(object):
    """Encapsulates global architecture specific data.

    Contains the performance event open syscall and ioctl numbers, as
    well as the VM exit reasons for the architecture it runs on.

    """
    @staticmethod
    def get_arch():
        machine = os.uname()[4]

        if machine.startswith('ppc'):
            return ArchPPC()
        elif machine.startswith('aarch64'):
            return ArchA64()
        elif machine.startswith('s390'):
            return ArchS390()
        else:
            # X86_64
            for line in open('/proc/cpuinfo'):
                if not line.startswith('flags'):
                    continue

                flags = line.split()
                if 'vmx' in flags:
                    return ArchX86(VMX_EXIT_REASONS)
                if 'svm' in flags:
                    return ArchX86(SVM_EXIT_REASONS)
                return

class ArchX86(Arch):
    def __init__(self, exit_reasons):
        self.sc_perf_evt_open = 298
        self.ioctl_numbers = IOCTL_NUMBERS
        self.exit_reasons = exit_reasons

class ArchPPC(Arch):
    def __init__(self):
        self.sc_perf_evt_open = 319
        self.ioctl_numbers = IOCTL_NUMBERS
        self.ioctl_numbers['ENABLE'] = 0x20002400
        self.ioctl_numbers['DISABLE'] = 0x20002401
        self.ioctl_numbers['RESET'] = 0x20002403

        # PPC comes in 32 and 64 bit and some generated ioctl
        # numbers depend on the wordsize.
        char_ptr_size = ctypes.sizeof(ctypes.c_char_p)
        self.ioctl_numbers['SET_FILTER'] = 0x80002406 | char_ptr_size << 16
        self.exit_reasons = {}

class ArchA64(Arch):
    def __init__(self):
        self.sc_perf_evt_open = 241
        self.ioctl_numbers = IOCTL_NUMBERS
        self.exit_reasons = AARCH64_EXIT_REASONS

class ArchS390(Arch):
    def __init__(self):
        self.sc_perf_evt_open = 331
        self.ioctl_numbers = IOCTL_NUMBERS
        self.exit_reasons = None

ARCH = Arch.get_arch()


def walkdir(path):
    """Returns os.walk() data for specified directory.

    As it is only a wrapper it returns the same 3-tuple of (dirpath,
    dirnames, filenames).
    """
    return next(os.walk(path))


def parse_int_list(list_string):
    """Returns an int list from a string of comma separated integers and
    integer ranges."""
    integers = []
    members = list_string.split(',')

    for member in members:
        if '-' not in member:
            integers.append(int(member))
        else:
            int_range = member.split('-')
            integers.extend(range(int(int_range[0]),
                                  int(int_range[1]) + 1))

    return integers


def get_online_cpus():
    """Returns a list of cpu id integers."""
    with open('/sys/devices/system/cpu/online') as cpu_list:
        cpu_string = cpu_list.readline()
        return parse_int_list(cpu_string)


def get_filters():
    """Returns a dict of trace events, their filter ids and
    the values that can be filtered.

    Trace events can be filtered for special values by setting a
    filter string via an ioctl. The string normally has the format
    identifier==value. For each filter a new event will be created, to
    be able to distinguish the events.

    """
    filters = {}
    filters['kvm_userspace_exit'] = ('reason', USERSPACE_EXIT_REASONS)
    if ARCH.exit_reasons:
        filters['kvm_exit'] = ('exit_reason', ARCH.exit_reasons)
    return filters

libc = ctypes.CDLL('libc.so.6', use_errno=True)
syscall = libc.syscall

class perf_event_attr(ctypes.Structure):
    """Struct that holds the necessary data to set up a trace event.

    For an extensive explanation see perf_event_open(2) and
    include/uapi/linux/perf_event.h, struct perf_event_attr

    All fields that are not initialized in the constructor are 0.

    """
    _fields_ = [('type', ctypes.c_uint32),
                ('size', ctypes.c_uint32),
                ('config', ctypes.c_uint64),
                ('sample_freq', ctypes.c_uint64),
                ('sample_type', ctypes.c_uint64),
                ('read_format', ctypes.c_uint64),
                ('flags', ctypes.c_uint64),
                ('wakeup_events', ctypes.c_uint32),
                ('bp_type', ctypes.c_uint32),
                ('bp_addr', ctypes.c_uint64),
                ('bp_len', ctypes.c_uint64),
                ]

    def __init__(self):
        super(self.__class__, self).__init__()
        self.type = PERF_TYPE_TRACEPOINT
        self.size = ctypes.sizeof(self)
        self.read_format = PERF_FORMAT_GROUP

def perf_event_open(attr, pid, cpu, group_fd, flags):
    """Wrapper for the sys_perf_evt_open() syscall.

    Used to set up performance events, returns a file descriptor or -1
    on error.

    Attributes are:
    - syscall number
    - struct perf_event_attr *
    - pid or -1 to monitor all pids
    - cpu number or -1 to monitor all cpus
    - The file descriptor of the group leader or -1 to create a group.
    - flags

    """
    return syscall(ARCH.sc_perf_evt_open, ctypes.pointer(attr),
                   ctypes.c_int(pid), ctypes.c_int(cpu),
                   ctypes.c_int(group_fd), ctypes.c_long(flags))

PERF_TYPE_TRACEPOINT = 2
PERF_FORMAT_GROUP = 1 << 3

PATH_DEBUGFS_TRACING = '/sys/kernel/debug/tracing'
PATH_DEBUGFS_KVM = '/sys/kernel/debug/kvm'

class Group(object):
    """Represents a perf event group."""

    def __init__(self):
        self.events = []

    def add_event(self, event):
        self.events.append(event)

    def read(self):
        """Returns a dict with 'event name: value' for all events in the
        group.

        Values are read by reading from the file descriptor of the
        event that is the group leader. See perf_event_open(2) for
        details.

        Read format for the used event configuration is:
        struct read_format {
            u64 nr; /* The number of events */
            struct {
                u64 value; /* The value of the event */
            } values[nr];
        };

        """
        length = 8 * (1 + len(self.events))
        read_format = 'xxxxxxxx' + 'Q' * len(self.events)
        return dict(zip([event.name for event in self.events],
                        struct.unpack(read_format,
                                      os.read(self.events[0].fd, length))))

class Event(object):
    """Represents a performance event and manages its life cycle."""
    def __init__(self, name, group, trace_cpu, trace_pid, trace_point,
                 trace_filter, trace_set='kvm'):
        self.name = name
        self.fd = None
        self.setup_event(group, trace_cpu, trace_pid, trace_point,
                         trace_filter, trace_set)

    def __del__(self):
        """Closes the event's file descriptor.

        As no python file object was created for the file descriptor,
        python will not reference count the descriptor and will not
        close it itself automatically, so we do it.

        """
        if self.fd:
            os.close(self.fd)

    def setup_event_attribute(self, trace_set, trace_point):
        """Returns an initialized ctype perf_event_attr struct."""

        id_path = os.path.join(PATH_DEBUGFS_TRACING, 'events', trace_set,
                               trace_point, 'id')

        event_attr = perf_event_attr()
        event_attr.config = int(open(id_path).read())
        return event_attr

    def setup_event(self, group, trace_cpu, trace_pid, trace_point,
                    trace_filter, trace_set):
        """Sets up the perf event in Linux.

        Issues the syscall to register the event in the kernel and
        then sets the optional filter.

        """

        event_attr = self.setup_event_attribute(trace_set, trace_point)

        # First event will be group leader.
        group_leader = -1

        # All others have to pass the leader's descriptor instead.
        if group.events:
            group_leader = group.events[0].fd

        fd = perf_event_open(event_attr, trace_pid,
                             trace_cpu, group_leader, 0)
        if fd == -1:
            err = ctypes.get_errno()
            raise OSError(err, os.strerror(err),
                          'while calling sys_perf_event_open().')

        if trace_filter:
            fcntl.ioctl(fd, ARCH.ioctl_numbers['SET_FILTER'],
                        trace_filter)

        self.fd = fd

    def enable(self):
        """Enables the trace event in the kernel.

        Enabling the group leader makes reading counters from it and the
        events under it possible.

        """
        fcntl.ioctl(self.fd, ARCH.ioctl_numbers['ENABLE'], 0)

    def disable(self):
        """Disables the trace event in the kernel.

        Disabling the group leader makes reading all counters under it
        impossible.

        """
        fcntl.ioctl(self.fd, ARCH.ioctl_numbers['DISABLE'], 0)

    def reset(self):
        """Resets the count of the trace event in the kernel."""
        fcntl.ioctl(self.fd, ARCH.ioctl_numbers['RESET'], 0)

class TracepointProvider(object):
    """Data provider for the stats class.

    Manages the events/groups from which it acquires its data.

    """
    def __init__(self):
        self.group_leaders = []
        self.filters = get_filters()
        self._fields = self.get_available_fields()
        self._pid = 0

    def get_available_fields(self):
        """Returns a list of available event's of format 'event name(filter
        name)'.

        All available events have directories under
        /sys/kernel/debug/tracing/events/ which export information
        about the specific event. Therefore, listing the dirs gives us
        a list of all available events.

        Some events like the vm exit reasons can be filtered for
        specific values. To take account for that, the routine below
        creates special fields with the following format:
        event name(filter name)

        """
        path = os.path.join(PATH_DEBUGFS_TRACING, 'events', 'kvm')
        fields = walkdir(path)[1]
        extra = []
        for field in fields:
            if field in self.filters:
                filter_name_, filter_dicts = self.filters[field]
                for name in filter_dicts:
                    extra.append(field + '(' + name + ')')
        fields += extra
        return fields

    def setup_traces(self):
        """Creates all event and group objects needed to be able to retrieve
        data."""
        if self._pid > 0:
            # Fetch list of all threads of the monitored pid, as qemu
            # starts a thread for each vcpu.
            path = os.path.join('/proc', str(self._pid), 'task')
            groupids = walkdir(path)[1]
        else:
            groupids = get_online_cpus()

        # The constant is needed as a buffer for python libs, std
        # streams and other files that the script opens.
        newlim = len(groupids) * len(self._fields) + 50
        try:
            softlim_, hardlim = resource.getrlimit(resource.RLIMIT_NOFILE)

            if hardlim < newlim:
                # Now we need CAP_SYS_RESOURCE, to increase the hard limit.
                resource.setrlimit(resource.RLIMIT_NOFILE, (newlim, newlim))
            else:
                # Raising the soft limit is sufficient.
                resource.setrlimit(resource.RLIMIT_NOFILE, (newlim, hardlim))

        except ValueError:
            sys.exit("NOFILE rlimit could not be raised to {0}".format(newlim))

        for groupid in groupids:
            group = Group()
            for name in self._fields:
                tracepoint = name
                tracefilter = None
                match = re.match(r'(.*)\((.*)\)', name)
                if match:
                    tracepoint, sub = match.groups()
                    tracefilter = ('%s==%d\0' %
                                   (self.filters[tracepoint][0],
                                    self.filters[tracepoint][1][sub]))

                # From perf_event_open(2):
                # pid > 0 and cpu == -1
                # This measures the specified process/thread on any CPU.
                #
                # pid == -1 and cpu >= 0
                # This measures all processes/threads on the specified CPU.
                trace_cpu = groupid if self._pid == 0 else -1
                trace_pid = int(groupid) if self._pid != 0 else -1

                group.add_event(Event(name=name,
                                      group=group,
                                      trace_cpu=trace_cpu,
                                      trace_pid=trace_pid,
                                      trace_point=tracepoint,
                                      trace_filter=tracefilter))

            self.group_leaders.append(group)

    def available_fields(self):
        return self.get_available_fields()

    @property
    def fields(self):
        return self._fields

    @fields.setter
    def fields(self, fields):
        """Enables/disables the (un)wanted events"""
        self._fields = fields
        for group in self.group_leaders:
            for index, event in enumerate(group.events):
                if event.name in fields:
                    event.reset()
                    event.enable()
                else:
                    # Do not disable the group leader.
                    # It would disable all of its events.
                    if index != 0:
                        event.disable()

    @property
    def pid(self):
        return self._pid

    @pid.setter
    def pid(self, pid):
        """Changes the monitored pid by setting new traces."""
        self._pid = pid
        # The garbage collector will get rid of all Event/Group
        # objects and open files after removing the references.
        self.group_leaders = []
        self.setup_traces()
        self.fields = self._fields

    def read(self):
        """Returns 'event name: current value' for all enabled events."""
        ret = defaultdict(int)
        for group in self.group_leaders:
            for name, val in group.read().iteritems():
                if name in self._fields:
                    ret[name] += val
        return ret

class DebugfsProvider(object):
    """Provides data from the files that KVM creates in the kvm debugfs
    folder."""
    def __init__(self):
        self._fields = self.get_available_fields()
        self._pid = 0
        self.do_read = True

    def get_available_fields(self):
        """"Returns a list of available fields.

        The fields are all available KVM debugfs files

        """
        return walkdir(PATH_DEBUGFS_KVM)[2]

    @property
    def fields(self):
        return self._fields

    @fields.setter
    def fields(self, fields):
        self._fields = fields

    @property
    def pid(self):
        return self._pid

    @pid.setter
    def pid(self, pid):
        if pid != 0:
            self._pid = pid

            vms = walkdir(PATH_DEBUGFS_KVM)[1]
            if len(vms) == 0:
                self.do_read = False

            self.paths = filter(lambda x: "{}-".format(pid) in x, vms)

        else:
            self.paths = ['']
            self.do_read = True

    def read(self):
        """Returns a dict with format:'file name / field -> current value'."""
        results = {}

        # If no debugfs filtering support is available, then don't read.
        if not self.do_read:
            return results

        for path in self.paths:
            for field in self._fields:
                results[field] = results.get(field, 0) \
                                 + self.read_field(field, path)

        return results

    def read_field(self, field, path):
        """Returns the value of a single field from a specific VM."""
        try:
            return int(open(os.path.join(PATH_DEBUGFS_KVM,
                                         path,
                                         field))
                       .read())
        except IOError:
            return 0

class Stats(object):
    """Manages the data providers and the data they provide.

    It is used to set filters on the provider's data and collect all
    provider data.

    """
    def __init__(self, providers, pid, fields=None):
        self.providers = providers
        self._pid_filter = pid
        self._fields_filter = fields
        self.values = {}
        self.update_provider_pid()
        self.update_provider_filters()

    def update_provider_filters(self):
        """Propagates fields filters to providers."""
        def wanted(key):
            if not self._fields_filter:
                return True
            return re.match(self._fields_filter, key) is not None

        # As we reset the counters when updating the fields we can
        # also clear the cache of old values.
        self.values = {}
        for provider in self.providers:
            provider_fields = [key for key in provider.get_available_fields()
                               if wanted(key)]
            provider.fields = provider_fields

    def update_provider_pid(self):
        """Propagates pid filters to providers."""
        for provider in self.providers:
            provider.pid = self._pid_filter

    @property
    def fields_filter(self):
        return self._fields_filter

    @fields_filter.setter
    def fields_filter(self, fields_filter):
        self._fields_filter = fields_filter
        self.update_provider_filters()

    @property
    def pid_filter(self):
        return self._pid_filter

    @pid_filter.setter
    def pid_filter(self, pid):
        self._pid_filter = pid
        self.values = {}
        self.update_provider_pid()

    def get(self):
        """Returns a dict with field -> (value, delta to last value) of all
        provider data."""
        for provider in self.providers:
            new = provider.read()
            for key in provider.fields:
                oldval = self.values.get(key, (0, 0))
                newval = new.get(key, 0)
                newdelta = None
                if oldval is not None:
                    newdelta = newval - oldval[0]
                self.values[key] = (newval, newdelta)
        return self.values

LABEL_WIDTH = 40
NUMBER_WIDTH = 10

class Tui(object):
    """Instruments curses to draw a nice text ui."""
    def __init__(self, stats):
        self.stats = stats
        self.screen = None
        self.drilldown = False
        self.update_drilldown()

    def __enter__(self):
        """Initialises curses for later use.  Based on curses.wrapper
           implementation from the Python standard library."""
        self.screen = curses.initscr()
        curses.noecho()
        curses.cbreak()

        # The try/catch works around a minor bit of
        # over-conscientiousness in the curses module, the error
        # return from C start_color() is ignorable.
        try:
            curses.start_color()
        except:
            pass

        curses.use_default_colors()
        return self

    def __exit__(self, *exception):
        """Resets the terminal to its normal state.  Based on curses.wrappre
           implementation from the Python standard library."""
        if self.screen:
            self.screen.keypad(0)
            curses.echo()
            curses.nocbreak()
            curses.endwin()

    def update_drilldown(self):
        """Sets or removes a filter that only allows fields without braces."""
        if not self.stats.fields_filter:
            self.stats.fields_filter = r'^[^\(]*$'

        elif self.stats.fields_filter == r'^[^\(]*$':
            self.stats.fields_filter = None

    def update_pid(self, pid):
        """Propagates pid selection to stats object."""
        self.stats.pid_filter = pid

    def refresh(self, sleeptime):
        """Refreshes on-screen data."""
        self.screen.erase()
        if self.stats.pid_filter > 0:
            self.screen.addstr(0, 0, 'kvm statistics - pid {0}'
                               .format(self.stats.pid_filter),
                               curses.A_BOLD)
        else:
            self.screen.addstr(0, 0, 'kvm statistics - summary', curses.A_BOLD)
        self.screen.addstr(2, 1, 'Event')
        self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH -
                           len('Total'), 'Total')
        self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH + 8 -
                           len('Current'), 'Current')
        row = 3
        stats = self.stats.get()
        def sortkey(x):
            if stats[x][1]:
                return (-stats[x][1], -stats[x][0])
            else:
                return (0, -stats[x][0])
        for key in sorted(stats.keys(), key=sortkey):

            if row >= self.screen.getmaxyx()[0]:
                break
            values = stats[key]
            if not values[0] and not values[1]:
                break
            col = 1
            self.screen.addstr(row, col, key)
            col += LABEL_WIDTH
            self.screen.addstr(row, col, '%10d' % (values[0],))
            col += NUMBER_WIDTH
            if values[1] is not None:
                self.screen.addstr(row, col, '%8d' % (values[1] / sleeptime,))
            row += 1
        self.screen.refresh()

    def show_filter_selection(self):
        """Draws filter selection mask.

        Asks for a valid regex and sets the fields filter accordingly.

        """
        while True:
            self.screen.erase()
            self.screen.addstr(0, 0,
                               "Show statistics for events matching a regex.",
                               curses.A_BOLD)
            self.screen.addstr(2, 0,
                               "Current regex: {0}"
                               .format(self.stats.fields_filter))
            self.screen.addstr(3, 0, "New regex: ")
            curses.echo()
            regex = self.screen.getstr()
            curses.noecho()
            if len(regex) == 0:
                return
            try:
                re.compile(regex)
                self.stats.fields_filter = regex
                return
            except re.error:
                continue

    def show_vm_selection(self):
        """Draws PID selection mask.

        Asks for a pid until a valid pid or 0 has been entered.

        """
        while True:
            self.screen.erase()
            self.screen.addstr(0, 0,
                               'Show statistics for specific pid.',
                               curses.A_BOLD)
            self.screen.addstr(1, 0,
                               'This might limit the shown data to the trace '
                               'statistics.')

            curses.echo()
            self.screen.addstr(3, 0, "Pid [0 or pid]: ")
            pid = self.screen.getstr()
            curses.noecho()

            try:
                pid = int(pid)

                if pid == 0:
                    self.update_pid(pid)
                    break
                else:
                    if not os.path.isdir(os.path.join('/proc/', str(pid))):
                        continue
                    else:
                        self.update_pid(pid)
                        break

            except ValueError:
                continue

    def show_stats(self):
        """Refreshes the screen and processes user input."""
        sleeptime = 0.25
        while True:
            self.refresh(sleeptime)
            curses.halfdelay(int(sleeptime * 10))
            sleeptime = 3
            try:
                char = self.screen.getkey()
                if char == 'x':
                    self.drilldown = not self.drilldown
                    self.update_drilldown()
                if char == 'q':
                    break
                if char == 'f':
                    self.show_filter_selection()
                if char == 'p':
                    self.show_vm_selection()
            except KeyboardInterrupt:
                break
            except curses.error:
                continue

def batch(stats):
    """Prints statistics in a key, value format."""
    s = stats.get()
    time.sleep(1)
    s = stats.get()
    for key in sorted(s.keys()):
        values = s[key]
        print '%-42s%10d%10d' % (key, values[0], values[1])

def log(stats):
    """Prints statistics as reiterating key block, multiple value blocks."""
    keys = sorted(stats.get().iterkeys())
    def banner():
        for k in keys:
            print '%s' % k,
        print
    def statline():
        s = stats.get()
        for k in keys:
            print ' %9d' % s[k][1],
        print
    line = 0
    banner_repeat = 20
    while True:
        time.sleep(1)
        if line % banner_repeat == 0:
            banner()
        statline()
        line += 1

def get_options():
    """Returns processed program arguments."""
    description_text = """
This script displays various statistics about VMs running under KVM.
The statistics are gathered from the KVM debugfs entries and / or the
currently available perf traces.

The monitoring takes additional cpu cycles and might affect the VM's
performance.

Requirements:
- Access to:
    /sys/kernel/debug/kvm
    /sys/kernel/debug/trace/events/*
    /proc/pid/task
- /proc/sys/kernel/perf_event_paranoid < 1 if user has no
  CAP_SYS_ADMIN and perf events are used.
- CAP_SYS_RESOURCE if the hard limit is not high enough to allow
  the large number of files that are possibly opened.
"""

    class PlainHelpFormatter(optparse.IndentedHelpFormatter):
        def format_description(self, description):
            if description:
                return description + "\n"
            else:
                return ""

    optparser = optparse.OptionParser(description=description_text,
                                      formatter=PlainHelpFormatter())
    optparser.add_option('-1', '--once', '--batch',
                         action='store_true',
                         default=False,
                         dest='once',
                         help='run in batch mode for one second',
                         )
    optparser.add_option('-l', '--log',
                         action='store_true',
                         default=False,
                         dest='log',
                         help='run in logging mode (like vmstat)',
                         )
    optparser.add_option('-t', '--tracepoints',
                         action='store_true',
                         default=False,
                         dest='tracepoints',
                         help='retrieve statistics from tracepoints',
                         )
    optparser.add_option('-d', '--debugfs',
                         action='store_true',
                         default=False,
                         dest='debugfs',
                         help='retrieve statistics from debugfs',
                         )
    optparser.add_option('-f', '--fields',
                         action='store',
                         default=None,
                         dest='fields',
                         help='fields to display (regex)',
                         )
    optparser.add_option('-p', '--pid',
                        action='store',
                        default=0,
                        type=int,
                        dest='pid',
                        help='restrict statistics to pid',
                        )
    (options, _) = optparser.parse_args(sys.argv)
    return options

def get_providers(options):
    """Returns a list of data providers depending on the passed options."""
    providers = []

    if options.tracepoints:
        providers.append(TracepointProvider())
    if options.debugfs:
        providers.append(DebugfsProvider())
    if len(providers) == 0:
        providers.append(TracepointProvider())

    return providers

def check_access(options):
    """Exits if the current user can't access all needed directories."""
    if not os.path.exists('/sys/kernel/debug'):
        sys.stderr.write('Please enable CONFIG_DEBUG_FS in your kernel.')
        sys.exit(1)

    if not os.path.exists(PATH_DEBUGFS_KVM):
        sys.stderr.write("Please make sure, that debugfs is mounted and "
                         "readable by the current user:\n"
                         "('mount -t debugfs debugfs /sys/kernel/debug')\n"
                         "Also ensure, that the kvm modules are loaded.\n")
        sys.exit(1)

    if not os.path.exists(PATH_DEBUGFS_TRACING) and (options.tracepoints
                                                     or not options.debugfs):
        sys.stderr.write("Please enable CONFIG_TRACING in your kernel "
                         "when using the option -t (default).\n"
                         "If it is enabled, make {0} readable by the "
                         "current user.\n"
                         .format(PATH_DEBUGFS_TRACING))
        if options.tracepoints:
            sys.exit(1)

        sys.stderr.write("Falling back to debugfs statistics!\n")
        options.debugfs = True
        sleep(5)

    return options

def main():
    options = get_options()
    options = check_access(options)

    if (options.pid > 0 and
        not os.path.isdir(os.path.join('/proc/',
                                       str(options.pid)))):
        sys.stderr.write('Did you use a (unsupported) tid instead of a pid?\n')
        sys.exit('Specified pid does not exist.')

    providers = get_providers(options)
    stats = Stats(providers, options.pid, fields=options.fields)

    if options.log:
        log(stats)
    elif not options.once:
        with Tui(stats) as tui:
            tui.show_stats()
    else:
        batch(stats)

if __name__ == "__main__":
    main()
OpenPOWER on IntegriCloud