Advantages over existing simpletrace backend:
- More than 6 elements (vitually unlimited) arguments can be traced.
- This allows to trace strings (variable size element) as well.
Signed-off-by: Harsh Prateek Bora <ha...@linux.vnet.ibm.com>
---
scripts/tracetool.py | 82 ++++++++++++++-----
trace/simple.c | 226 ++++++++++++++++++++++++++++----------------------
trace/simple.h | 38 +++++++--
3 files changed, 218 insertions(+), 128 deletions(-)
diff --git a/scripts/tracetool.py b/scripts/tracetool.py
index 6cbbdd7..1073818 100755
--- a/scripts/tracetool.py
+++ b/scripts/tracetool.py
@@ -178,43 +178,83 @@ def nop_c(events):
def simple_h(events):
print '#include "trace/simple.h"'
print
-
- for num, event in enumerate(events):
- if len(event.args):
- argstr = event.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)
-
- print '''static inline void trace_%(name)s(%(args)s)
-{
- trace%(argc)d(%(trace_args)s);
-}''' % {
+ for event in events:
+ print 'void trace_%(name)s(%(args)s);' % {
'name': event.name,
- 'args': event.args,
- 'argc': len(event.args),
- 'trace_args': simple_args
+ 'args': event.args
}
- print
+ print
print '#define NR_TRACE_EVENTS %d' % len(events)
print 'extern TraceEvent trace_list[NR_TRACE_EVENTS];'
-
@for_backend("simple", "c")
def simple_c(events):
print '#include "trace.h"'
+ print '#include "trace/simple.h"'
print
print 'TraceEvent trace_list[] = {'
print
-
for event in events:
print '{.tp_name = "%(name)s", .state=0},' % {
- 'name': event.name,
+ 'name': event.name
}
print
print '};'
+ print
+
+ for num, event in enumerate(events):
+ sizes = []
+ for type_, name in event.args:
+ if type_is_string(type_):
+ sizes.append("4 + strlen(%s)" % name)
+ else:
+ sizes.append("8")
+ sizestr = " + ".join(sizes)
+ if len(event.args) == 0:
+ sizestr = '0'
+
+ print '''void trace_%(name)s(%(args)s)
+{
+ TraceBufferRecord rec;
+
+ if (!trace_list[%(event_id)s].state) {
+ return;
+ }
+
+ if (trace_record_start(&rec, %(event_id)s, %(sizestr)s)) {
+ return; /* Trace Buffer Full, Event Dropped ! */
+ }
+''' % {
+ 'name': event.name,
+ 'args': event.args,
+ 'event_id': num,
+ 'sizestr': sizestr,
+}
+ if len(event.args) > 0:
+ for type_, name in event.args:
+ # string
+ if type_is_string(type_):
+ print '''
+ trace_record_write_str(&rec, %(name)s);''' % {
+ 'name': name
+}
+ # pointer var (not string)
+ elif type_.endswith('*'):
+ print '''
+ trace_record_write_u64(&rec, (uint64_t)(uint64_t *)%(name)s);''' % {
+ 'name': name
+}
+ # primitive data type
+ else:
+ print '''
+ trace_record_write_u64(&rec, (uint64_t)%(name)s);''' % {
+ 'name': name
+}
+
+ print '''
+ trace_record_finish(&rec);
+}
+'''
##################################################
# backend: stderr
diff --git a/trace/simple.c b/trace/simple.c
index b639dda..de5c3d3 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 +45,35 @@ 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[]; /* arguments position affects ST_REC_HDR_LEN */
+} TraceRecord;
+
+/* * Trace record header length */
+#define ST_REC_HDR_LEN 24
+
+int trace_alloc_record(TraceBufferRecord *rec, TraceEventID event, uint32_t
datasize);
+static void read_from_buffer(unsigned int idx, uint8_t *dataptr, uint32_t
size);
+static void write_to_buffer(unsigned int idx, uint8_t *dataptr, uint32_t size);
+void trace_mark_record_complete(TraceBufferRecord *rec);
+
/**
* Read a trace record from the trace buffer
*
@@ -75,16 +82,22 @@ 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)) {
+ uint8_t temp_rec[ST_REC_HDR_LEN];
+ TraceRecord *record = (TraceRecord *) temp_rec;
+ read_from_buffer(idx, temp_rec, ST_REC_HDR_LEN);
+
+ 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;
+ *recordptr = g_malloc(record->length);
+ /* make a copy of record to avoid being overwritten */
+ read_from_buffer(idx, (uint8_t *)*recordptr, record->length);
+ (*recordptr)->event &= ~TRACE_RECORD_VALID;
return true;
}
@@ -120,29 +133,31 @@ 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;
+ unsigned int idx = 0;
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) {
+ recordptr = g_malloc(ST_REC_HDR_LEN + sizeof(dropped_events));
+ recordptr->event = DROPPED_EVENT_ID,
+ recordptr->timestamp_ns = get_clock();
+ recordptr->length = ST_REC_HDR_LEN + sizeof(dropped_events),
+ recordptr->reserved = 0;
+ *(uint64_t *) &(recordptr->arguments[0]) = dropped_events;
+ dropped_events = 0;
+ unused = fwrite(recordptr, recordptr->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;
+ g_free(recordptr);
+ recordptr = (TraceRecord *) &trace_buf[idx];
+ recordptr->event = 0;
+ idx = writeout_idx % TRACE_BUF_LEN;
}
fflush(trace_fp);
@@ -150,72 +165,101 @@ 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)
+int trace_record_start(TraceBufferRecord *rec, TraceEventID id, size_t arglen)
{
- unsigned int idx;
- uint64_t timestamp;
-
- if (!trace_list[event].state) {
- return;
- }
-
- timestamp = get_clock();
-
- idx = g_atomic_int_exchange_and_add((gint *)&trace_idx, 1) % TRACE_BUF_LEN;
- 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);
- }
+ return trace_alloc_record(rec, id, arglen); /* return 0 on success */
}
-void trace0(TraceEventID event)
+void trace_record_write_u64(TraceBufferRecord *rec, uint64_t val)
{
- trace(event, 0, 0, 0, 0, 0, 0);
+ write_to_buffer(rec->rec_off, (uint8_t *)&val, sizeof(uint64_t));
+ rec->rec_off += sizeof(uint64_t);
}
-void trace1(TraceEventID event, uint64_t x1)
+void trace_record_write_str(TraceBufferRecord *rec, const char *s)
{
- trace(event, x1, 0, 0, 0, 0, 0);
+ /* Write string length first */
+ uint32_t slen = strlen(s);
+ write_to_buffer(rec->rec_off, (uint8_t *)&slen, sizeof(slen));
+ rec->rec_off += sizeof(slen);
+ /* Write actual string now */
+ write_to_buffer(rec->rec_off, (uint8_t *)s, slen);
+ rec->rec_off += slen;
}
-void trace2(TraceEventID event, uint64_t x1, uint64_t x2)
+void trace_record_finish(TraceBufferRecord *rec)
{
- trace(event, x1, x2, 0, 0, 0, 0);
+ trace_mark_record_complete(rec);
}
-void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3)
+int trace_alloc_record(TraceBufferRecord *rec, TraceEventID event, uint32_t
datasize)
{
- trace(event, x1, x2, x3, 0, 0, 0);
+ unsigned int idx, rec_off;
+ uint32_t rec_len = ST_REC_HDR_LEN + datasize;
+ uint64_t timestamp_ns = get_clock();
+
+ if ((rec_len + trace_idx - writeout_idx) > TRACE_BUF_LEN) {
+ /* Trace Buffer Full, Event dropped ! */
+ dropped_events++;
+ return 1;
+ }
+ idx = g_atomic_int_exchange_and_add((gint *)&trace_idx, rec_len) %
TRACE_BUF_LEN;
+
+ /* To check later if threshold crossed */
+ rec->next_tbuf_idx = trace_idx % TRACE_BUF_LEN;
+
+ rec_off = idx;
+ write_to_buffer(rec_off, (uint8_t*)&event, sizeof(event));
+ rec_off += sizeof(event);
+ write_to_buffer(rec_off, (uint8_t*)×tamp_ns, sizeof(timestamp_ns));
+ rec_off += sizeof(timestamp_ns);
+ write_to_buffer(rec_off, (uint8_t*)&rec_len, sizeof(rec_len));
+ rec_off += sizeof(rec_len);
+
+ rec->tbuf_idx = idx;
+ rec->rec_off = (idx + ST_REC_HDR_LEN) % 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, uint8_t *dataptr, uint32_t size)
{
- trace(event, x1, x2, x3, x4, 0, 0);
+ uint32_t x = 0;
+ while (x < size) {
+ if (idx >= TRACE_BUF_LEN) {
+ idx = idx % TRACE_BUF_LEN;
+ }
+ dataptr[x++] = trace_buf[idx++];
+ }
}
-void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,
uint64_t x4, uint64_t x5)
+static void write_to_buffer(unsigned int idx, uint8_t *dataptr, uint32_t size)
{
- trace(event, x1, x2, x3, x4, x5, 0);
+ uint32_t x = 0;
+ while (x < size) {
+ if (idx >= TRACE_BUF_LEN) {
+ idx = idx % TRACE_BUF_LEN;
+ }
+ trace_buf[idx++] = dataptr[x++];
+ }
}
-void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,
uint64_t x4, uint64_t x5, uint64_t x6)
+void trace_mark_record_complete(TraceBufferRecord *rec)
{
- trace(event, x1, x2, x3, x4, x5, x6);
+ uint8_t temp_rec[ST_REC_HDR_LEN];
+ TraceRecord *record = (TraceRecord *) temp_rec;
+ read_from_buffer(rec->tbuf_idx, temp_rec, ST_REC_HDR_LEN);
+ __sync_synchronize(); /* write barrier before marking as valid */
+ record->event |= TRACE_RECORD_VALID;
+ write_to_buffer(rec->tbuf_idx, temp_rec, ST_REC_HDR_LEN);
+
+ if (rec->next_tbuf_idx > TRACE_BUF_FLUSH_THRESHOLD &&
+ rec->tbuf_idx <= TRACE_BUF_FLUSH_THRESHOLD) {
+ flush_trace_file(false);
+ }
}
+
+
void st_set_trace_file_enabled(bool enable)
{
if (enable == !!trace_fp) {
@@ -231,7 +275,8 @@ void st_set_trace_file_enabled(bool enable)
static const TraceRecord header = {
.event = HEADER_EVENT_ID,
.timestamp_ns = HEADER_MAGIC,
- .x1 = HEADER_VERSION,
+ /* Older log readers will check for version at next location */
+ .length = HEADER_VERSION,
};
trace_fp = fopen(trace_file_name, "wb");
@@ -288,23 +333,6 @@ void st_print_trace_file_status(FILE *stream, int
(*stream_printf)(FILE *stream,
trace_file_name, trace_fp ? "on" : "off");
}
-void st_print_trace(FILE *stream, int (*stream_printf)(FILE *stream, const
char *fmt, ...))
-{
- unsigned int i;
-
- for (i = 0; i < TRACE_BUF_LEN; i++) {
- TraceRecord record;
-
- if (!get_trace_record(i, &record)) {
- continue;
- }
- stream_printf(stream, "Event %" PRIu64 " : %" PRIx64 " %" PRIx64
- " %" PRIx64 " %" PRIx64 " %" PRIx64 " %" PRIx64 "\n",
- record.event, record.x1, record.x2,
- record.x3, record.x4, record.x5,
- record.x6);
- }
-}
void st_flush_trace_buffer(void)
{
diff --git a/trace/simple.h b/trace/simple.h
index 466e75b..6755e99 100644
--- a/trace/simple.h
+++ b/trace/simple.h
@@ -22,17 +22,39 @@ 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 *stream, fprintf_function stream_printf);
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;
+
+/**
+ * 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);
+
+/**
+ * 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 */
--
1.7.1.1
