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authorHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>2008-01-29 14:27:30 +0900
committerTony Luck <tony.luck@intel.com>2008-02-20 12:55:37 -0800
commitb64f34cdfe5bef9dfed1304c513220b0f2862eca (patch)
tree04cb9216a9de18afcb27f9bac3fda1f3c7bacbbd /arch/ia64/kernel/fsys.S
parent5d9c4a7de64d398604a978d267a6987f1f4025b7 (diff)
downloadop-kernel-dev-b64f34cdfe5bef9dfed1304c513220b0f2862eca.zip
op-kernel-dev-b64f34cdfe5bef9dfed1304c513220b0f2862eca.tar.gz
[IA64] VIRT_CPU_ACCOUNTING (accurate cpu time accounting)
This patch implements VIRT_CPU_ACCOUNTING for ia64, which enable us to use more accurate cpu time accounting. The VIRT_CPU_ACCOUNTING is an item of kernel config, which s390 and powerpc arch have. By turning this config on, these archs change the mechanism of cpu time accounting from tick-sampling based one to state-transition based one. The state-transition based accounting is done by checking time (cycle counter in processor) at every state-transition point, such as entrance/exit of kernel, interrupt, softirq etc. The difference between point to point is the actual time consumed during in the state. There is no doubt about that this value is more accurate than that of tick-sampling based accounting. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/kernel/fsys.S')
-rw-r--r--arch/ia64/kernel/fsys.S26
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S
index 4484197..c932d86 100644
--- a/arch/ia64/kernel/fsys.S
+++ b/arch/ia64/kernel/fsys.S
@@ -660,7 +660,11 @@ GLOBAL_ENTRY(fsys_bubble_down)
nop.i 0
;;
mov ar.rsc=0 // M2 set enforced lazy mode, pl 0, LE, loadrs=0
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+ mov.m r30=ar.itc // M get cycle for accounting
+#else
nop.m 0
+#endif
nop.i 0
;;
mov r23=ar.bspstore // M2 (12 cyc) save ar.bspstore
@@ -682,6 +686,28 @@ GLOBAL_ENTRY(fsys_bubble_down)
cmp.ne pKStk,pUStk=r0,r0 // A set pKStk <- 0, pUStk <- 1
br.call.sptk.many b7=ia64_syscall_setup // B
;;
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+ // mov.m r30=ar.itc is called in advance
+ add r16=TI_AC_STAMP+IA64_TASK_SIZE,r2
+ add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r2
+ ;;
+ ld8 r18=[r16],TI_AC_STIME-TI_AC_STAMP // time at last check in kernel
+ ld8 r19=[r17],TI_AC_UTIME-TI_AC_LEAVE // time at leave kernel
+ ;;
+ ld8 r20=[r16],TI_AC_STAMP-TI_AC_STIME // cumulated stime
+ ld8 r21=[r17] // cumulated utime
+ sub r22=r19,r18 // stime before leave kernel
+ ;;
+ st8 [r16]=r30,TI_AC_STIME-TI_AC_STAMP // update stamp
+ sub r18=r30,r19 // elapsed time in user mode
+ ;;
+ add r20=r20,r22 // sum stime
+ add r21=r21,r18 // sum utime
+ ;;
+ st8 [r16]=r20 // update stime
+ st8 [r17]=r21 // update utime
+ ;;
+#endif
mov ar.rsc=0x3 // M2 set eager mode, pl 0, LE, loadrs=0
mov rp=r14 // I0 set the real return addr
and r3=_TIF_SYSCALL_TRACEAUDIT,r3 // A
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