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-rw-r--r--scripts/tracetool/backend/simple.py90
-rw-r--r--trace/simple.c253
-rw-r--r--trace/simple.h39
3 files changed, 262 insertions, 120 deletions
diff --git a/scripts/tracetool/backend/simple.py b/scripts/tracetool/backend/simple.py
index fbb5717..c7e47d6 100644
--- a/scripts/tracetool/backend/simple.py
+++ b/scripts/tracetool/backend/simple.py
@@ -15,9 +15,16 @@ __email__ = "stefanha@linux.vnet.ibm.com"
from tracetool import out
+def is_string(arg):
+ strtype = ('const char*', 'char*', 'const char *', 'char *')
+ if arg.lstrip().startswith(strtype):
+ return True
+ else:
+ return False
def c(events):
out('#include "trace.h"',
+ '#include "trace/simple.h"',
'',
'TraceEvent trace_list[] = {')
@@ -26,30 +33,75 @@ def c(events):
name = e.name,
)
- out('};')
+ out('};',
+ '')
+
+ for num, event in enumerate(events):
+ out('void trace_%(name)s(%(args)s)',
+ '{',
+ ' TraceBufferRecord rec;',
+ name = event.name,
+ args = event.args,
+ )
+ sizes = []
+ for type_, name in event.args:
+ if is_string(type_):
+ out(' size_t arg%(name)s_len = %(name)s ? MIN(strlen(%(name)s), MAX_TRACE_STRLEN) : 0;',
+ name = name,
+ )
+ strsizeinfo = "4 + arg%s_len" % name
+ sizes.append(strsizeinfo)
+ else:
+ sizes.append("8")
+ sizestr = " + ".join(sizes)
+ if len(event.args) == 0:
+ sizestr = '0'
+
+
+ out('',
+ ' if (!trace_list[%(event_id)s].state) {',
+ ' return;',
+ ' }',
+ '',
+ ' if (trace_record_start(&rec, %(event_id)s, %(size_str)s)) {',
+ ' return; /* Trace Buffer Full, Event Dropped ! */',
+ ' }',
+ event_id = num,
+ size_str = sizestr,
+ )
+
+ if len(event.args) > 0:
+ for type_, name in event.args:
+ # string
+ if is_string(type_):
+ out(' trace_record_write_str(&rec, %(name)s, arg%(name)s_len);',
+ name = name,
+ )
+ # pointer var (not string)
+ elif type_.endswith('*'):
+ out(' trace_record_write_u64(&rec, (uint64_t)(uint64_t *)%(name)s);',
+ name = name,
+ )
+ # primitive data type
+ else:
+ out(' trace_record_write_u64(&rec, (uint64_t)%(name)s);',
+ name = name,
+ )
+
+ out(' trace_record_finish(&rec);',
+ '}',
+ '')
+
def h(events):
out('#include "trace/simple.h"',
'')
- for num, e in enumerate(events):
- if len(e.args):
- argstr = e.args.names()
- arg_prefix = ', (uint64_t)(uintptr_t)'
- cast_args = arg_prefix + arg_prefix.join(argstr)
- simple_args = (str(num) + cast_args)
- else:
- simple_args = str(num)
-
- out('static inline void trace_%(name)s(%(args)s)',
- '{',
- ' trace%(argc)d(%(trace_args)s);',
- '}',
- name = e.name,
- args = e.args,
- argc = len(e.args),
- trace_args = simple_args,
+ for event in events:
+ out('void trace_%(name)s(%(args)s);',
+ name = event.name,
+ args = event.args,
)
-
+ out('')
out('#define NR_TRACE_EVENTS %d' % len(events))
out('extern TraceEvent trace_list[NR_TRACE_EVENTS];')
diff --git a/trace/simple.c b/trace/simple.c
index b64bcf4..b700ea3 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -27,7 +27,7 @@
#define HEADER_MAGIC 0xf2b177cb0aa429b4ULL
/** Trace file version number, bump if format changes */
-#define HEADER_VERSION 0
+#define HEADER_VERSION 2
/** Records were dropped event ID */
#define DROPPED_EVENT_ID (~(uint64_t)0 - 1)
@@ -35,23 +35,6 @@
/** Trace record is valid */
#define TRACE_RECORD_VALID ((uint64_t)1 << 63)
-/** Trace buffer entry */
-typedef struct {
- uint64_t event;
- uint64_t timestamp_ns;
- uint64_t x1;
- uint64_t x2;
- uint64_t x3;
- uint64_t x4;
- uint64_t x5;
- uint64_t x6;
-} TraceRecord;
-
-enum {
- TRACE_BUF_LEN = 4096,
- TRACE_BUF_FLUSH_THRESHOLD = TRACE_BUF_LEN / 4,
-};
-
/*
* Trace records are written out by a dedicated thread. The thread waits for
* records to become available, writes them out, and then waits again.
@@ -62,11 +45,48 @@ static GCond *trace_empty_cond;
static bool trace_available;
static bool trace_writeout_enabled;
-static TraceRecord trace_buf[TRACE_BUF_LEN];
+enum {
+ TRACE_BUF_LEN = 4096 * 64,
+ TRACE_BUF_FLUSH_THRESHOLD = TRACE_BUF_LEN / 4,
+};
+
+uint8_t trace_buf[TRACE_BUF_LEN];
static unsigned int trace_idx;
+static unsigned int writeout_idx;
+static uint64_t dropped_events;
static FILE *trace_fp;
static char *trace_file_name = NULL;
+/* * Trace buffer entry */
+typedef struct {
+ uint64_t event; /* TraceEventID */
+ uint64_t timestamp_ns;
+ uint32_t length; /* in bytes */
+ uint32_t reserved; /* unused */
+ uint8_t arguments[];
+} TraceRecord;
+
+typedef struct {
+ uint64_t header_event_id; /* HEADER_EVENT_ID */
+ uint64_t header_magic; /* HEADER_MAGIC */
+ uint64_t header_version; /* HEADER_VERSION */
+} TraceRecordHeader;
+
+
+static void read_from_buffer(unsigned int idx, void *dataptr, size_t size);
+static unsigned int write_to_buffer(unsigned int idx, void *dataptr, size_t size);
+
+static void clear_buffer_range(unsigned int idx, size_t len)
+{
+ uint32_t num = 0;
+ while (num < len) {
+ if (idx >= TRACE_BUF_LEN) {
+ idx = idx % TRACE_BUF_LEN;
+ }
+ trace_buf[idx++] = 0;
+ num++;
+ }
+}
/**
* Read a trace record from the trace buffer
*
@@ -75,16 +95,30 @@ static char *trace_file_name = NULL;
*
* Returns false if the record is not valid.
*/
-static bool get_trace_record(unsigned int idx, TraceRecord *record)
+static bool get_trace_record(unsigned int idx, TraceRecord **recordptr)
{
- if (!(trace_buf[idx].event & TRACE_RECORD_VALID)) {
+ uint64_t event_flag = 0;
+ TraceRecord record;
+ /* read the event flag to see if its a valid record */
+ read_from_buffer(idx, &record, sizeof(event_flag));
+
+ if (!(record.event & TRACE_RECORD_VALID)) {
return false;
}
- __sync_synchronize(); /* read memory barrier before accessing record */
-
- *record = trace_buf[idx];
- record->event &= ~TRACE_RECORD_VALID;
+ smp_rmb(); /* read memory barrier before accessing record */
+ /* read the record header to know record length */
+ read_from_buffer(idx, &record, sizeof(TraceRecord));
+ *recordptr = malloc(record.length); /* dont use g_malloc, can deadlock when traced */
+ /* make a copy of record to avoid being overwritten */
+ read_from_buffer(idx, *recordptr, record.length);
+ smp_rmb(); /* memory barrier before clearing valid flag */
+ (*recordptr)->event &= ~TRACE_RECORD_VALID;
+ /* clear the trace buffer range for consumed record otherwise any byte
+ * with its MSB set may be considered as a valid event id when the writer
+ * thread crosses this range of buffer again.
+ */
+ clear_buffer_range(idx, record.length);
return true;
}
@@ -120,29 +154,39 @@ static void wait_for_trace_records_available(void)
static gpointer writeout_thread(gpointer opaque)
{
- TraceRecord record;
- unsigned int writeout_idx = 0;
- unsigned int num_available, idx;
+ TraceRecord *recordptr;
+ union {
+ TraceRecord rec;
+ uint8_t bytes[sizeof(TraceRecord) + sizeof(uint64_t)];
+ } dropped;
+ unsigned int idx = 0;
+ uint64_t dropped_count;
size_t unused __attribute__ ((unused));
for (;;) {
wait_for_trace_records_available();
- num_available = trace_idx - writeout_idx;
- if (num_available > TRACE_BUF_LEN) {
- record = (TraceRecord){
- .event = DROPPED_EVENT_ID,
- .x1 = num_available,
- };
- unused = fwrite(&record, sizeof(record), 1, trace_fp);
- writeout_idx += num_available;
+ if (dropped_events) {
+ dropped.rec.event = DROPPED_EVENT_ID,
+ dropped.rec.timestamp_ns = get_clock();
+ dropped.rec.length = sizeof(TraceRecord) + sizeof(dropped_events),
+ dropped.rec.reserved = 0;
+ while (1) {
+ dropped_count = dropped_events;
+ if (g_atomic_int_compare_and_exchange((gint *)&dropped_events,
+ dropped_count, 0)) {
+ break;
+ }
+ }
+ memcpy(dropped.rec.arguments, &dropped_count, sizeof(uint64_t));
+ unused = fwrite(&dropped.rec, dropped.rec.length, 1, trace_fp);
}
- idx = writeout_idx % TRACE_BUF_LEN;
- while (get_trace_record(idx, &record)) {
- trace_buf[idx].event = 0; /* clear valid bit */
- unused = fwrite(&record, sizeof(record), 1, trace_fp);
- idx = ++writeout_idx % TRACE_BUF_LEN;
+ while (get_trace_record(idx, &recordptr)) {
+ unused = fwrite(recordptr, recordptr->length, 1, trace_fp);
+ writeout_idx += recordptr->length;
+ free(recordptr); /* dont use g_free, can deadlock when traced */
+ idx = writeout_idx % TRACE_BUF_LEN;
}
fflush(trace_fp);
@@ -150,73 +194,93 @@ static gpointer writeout_thread(gpointer opaque)
return NULL;
}
-static void trace(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,
- uint64_t x4, uint64_t x5, uint64_t x6)
+void trace_record_write_u64(TraceBufferRecord *rec, uint64_t val)
{
- unsigned int idx;
- uint64_t timestamp;
-
- if (!trace_list[event].state) {
- return;
- }
-
- timestamp = get_clock();
-#if GLIB_CHECK_VERSION(2, 30, 0)
- idx = g_atomic_int_add((gint *)&trace_idx, 1) % TRACE_BUF_LEN;
-#else
- idx = g_atomic_int_exchange_and_add((gint *)&trace_idx, 1) % TRACE_BUF_LEN;
-#endif
- trace_buf[idx] = (TraceRecord){
- .event = event,
- .timestamp_ns = timestamp,
- .x1 = x1,
- .x2 = x2,
- .x3 = x3,
- .x4 = x4,
- .x5 = x5,
- .x6 = x6,
- };
- __sync_synchronize(); /* write barrier before marking as valid */
- trace_buf[idx].event |= TRACE_RECORD_VALID;
-
- if ((idx + 1) % TRACE_BUF_FLUSH_THRESHOLD == 0) {
- flush_trace_file(false);
- }
+ rec->rec_off = write_to_buffer(rec->rec_off, &val, sizeof(uint64_t));
}
-void trace0(TraceEventID event)
+void trace_record_write_str(TraceBufferRecord *rec, const char *s, uint32_t slen)
{
- trace(event, 0, 0, 0, 0, 0, 0);
+ /* Write string length first */
+ rec->rec_off = write_to_buffer(rec->rec_off, &slen, sizeof(slen));
+ /* Write actual string now */
+ rec->rec_off = write_to_buffer(rec->rec_off, (void*)s, slen);
}
-void trace1(TraceEventID event, uint64_t x1)
+int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasize)
{
- trace(event, x1, 0, 0, 0, 0, 0);
-}
+ unsigned int idx, rec_off, old_idx, new_idx;
+ uint32_t rec_len = sizeof(TraceRecord) + datasize;
+ uint64_t timestamp_ns = get_clock();
+
+ while (1) {
+ old_idx = trace_idx;
+ smp_rmb();
+ new_idx = old_idx + rec_len;
+
+ if (new_idx - writeout_idx > TRACE_BUF_LEN) {
+ /* Trace Buffer Full, Event dropped ! */
+ g_atomic_int_inc((gint *)&dropped_events);
+ return -ENOSPC;
+ }
-void trace2(TraceEventID event, uint64_t x1, uint64_t x2)
-{
- trace(event, x1, x2, 0, 0, 0, 0);
-}
+ if (g_atomic_int_compare_and_exchange((gint *)&trace_idx,
+ old_idx, new_idx)) {
+ break;
+ }
+ }
-void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3)
-{
- trace(event, x1, x2, x3, 0, 0, 0);
+ idx = old_idx % TRACE_BUF_LEN;
+ /* To check later if threshold crossed */
+ rec->next_tbuf_idx = new_idx % TRACE_BUF_LEN;
+
+ rec_off = idx;
+ rec_off = write_to_buffer(rec_off, (uint8_t*)&event, sizeof(event));
+ rec_off = write_to_buffer(rec_off, (uint8_t*)&timestamp_ns, sizeof(timestamp_ns));
+ rec_off = write_to_buffer(rec_off, (uint8_t*)&rec_len, sizeof(rec_len));
+
+ rec->tbuf_idx = idx;
+ rec->rec_off = (idx + sizeof(TraceRecord)) % TRACE_BUF_LEN;
+ return 0;
}
-void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4)
+static void read_from_buffer(unsigned int idx, void *dataptr, size_t size)
{
- trace(event, x1, x2, x3, x4, 0, 0);
+ uint8_t *data_ptr = dataptr;
+ uint32_t x = 0;
+ while (x < size) {
+ if (idx >= TRACE_BUF_LEN) {
+ idx = idx % TRACE_BUF_LEN;
+ }
+ data_ptr[x++] = trace_buf[idx++];
+ }
}
-void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5)
+static unsigned int write_to_buffer(unsigned int idx, void *dataptr, size_t size)
{
- trace(event, x1, x2, x3, x4, x5, 0);
+ uint8_t *data_ptr = dataptr;
+ uint32_t x = 0;
+ while (x < size) {
+ if (idx >= TRACE_BUF_LEN) {
+ idx = idx % TRACE_BUF_LEN;
+ }
+ trace_buf[idx++] = data_ptr[x++];
+ }
+ return idx; /* most callers wants to know where to write next */
}
-void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5, uint64_t x6)
+void trace_record_finish(TraceBufferRecord *rec)
{
- trace(event, x1, x2, x3, x4, x5, x6);
+ uint8_t temp_rec[sizeof(TraceRecord)];
+ TraceRecord *record = (TraceRecord *) temp_rec;
+ read_from_buffer(rec->tbuf_idx, temp_rec, sizeof(TraceRecord));
+ smp_wmb(); /* write barrier before marking as valid */
+ record->event |= TRACE_RECORD_VALID;
+ write_to_buffer(rec->tbuf_idx, temp_rec, sizeof(TraceRecord));
+
+ if ((trace_idx - writeout_idx) > TRACE_BUF_FLUSH_THRESHOLD) {
+ flush_trace_file(false);
+ }
}
void st_set_trace_file_enabled(bool enable)
@@ -231,10 +295,11 @@ void st_set_trace_file_enabled(bool enable)
flush_trace_file(true);
if (enable) {
- static const TraceRecord header = {
- .event = HEADER_EVENT_ID,
- .timestamp_ns = HEADER_MAGIC,
- .x1 = HEADER_VERSION,
+ static const TraceRecordHeader header = {
+ .header_event_id = HEADER_EVENT_ID,
+ .header_magic = HEADER_MAGIC,
+ /* Older log readers will check for version at next location */
+ .header_version = HEADER_VERSION,
};
trace_fp = fopen(trace_file_name, "wb");
diff --git a/trace/simple.h b/trace/simple.h
index 6b5358c..7e521c1 100644
--- a/trace/simple.h
+++ b/trace/simple.h
@@ -22,16 +22,41 @@ typedef struct {
bool state;
} TraceEvent;
-void trace0(TraceEventID event);
-void trace1(TraceEventID event, uint64_t x1);
-void trace2(TraceEventID event, uint64_t x1, uint64_t x2);
-void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3);
-void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4);
-void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5);
-void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5, uint64_t x6);
void st_print_trace_file_status(FILE *stream, fprintf_function stream_printf);
void st_set_trace_file_enabled(bool enable);
bool st_set_trace_file(const char *file);
void st_flush_trace_buffer(void);
+typedef struct {
+ unsigned int tbuf_idx;
+ unsigned int next_tbuf_idx;
+ unsigned int rec_off;
+} TraceBufferRecord;
+
+/* Note for hackers: Make sure MAX_TRACE_LEN < sizeof(uint32_t) */
+#define MAX_TRACE_STRLEN 512
+/**
+ * Initialize a trace record and claim space for it in the buffer
+ *
+ * @arglen number of bytes required for arguments
+ */
+int trace_record_start(TraceBufferRecord *rec, TraceEventID id, size_t arglen);
+
+/**
+ * Append a 64-bit argument to a trace record
+ */
+void trace_record_write_u64(TraceBufferRecord *rec, uint64_t val);
+
+/**
+ * Append a string argument to a trace record
+ */
+void trace_record_write_str(TraceBufferRecord *rec, const char *s, uint32_t slen);
+
+/**
+ * Mark a trace record completed
+ *
+ * Don't append any more arguments to the trace record after calling this.
+ */
+void trace_record_finish(TraceBufferRecord *rec);
+
#endif /* TRACE_SIMPLE_H */
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