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>
---
monitor.c | 2 +-
trace/simple.c | 178 ++++++++++++++++++++------------------------------------
trace/simple.h | 31 ++++++++--
3 files changed, 88 insertions(+), 123 deletions(-)
diff --git a/monitor.c b/monitor.c
index ffda0fe..b6f85d1 100644
--- a/monitor.c
+++ b/monitor.c
@@ -945,7 +945,7 @@ static void do_info_cpu_stats(Monitor *mon)
#if defined(CONFIG_TRACE_SIMPLE)
static void do_info_trace(Monitor *mon)
{
- st_print_trace((FILE *)mon, &monitor_fprintf);
+ /* FIXME: st_print_trace((FILE *)mon, &monitor_fprintf); */
}
#endif
diff --git a/trace/simple.c b/trace/simple.c
index b639dda..65cafe2 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 +45,12 @@ static GCond *trace_empty_cond;
static bool trace_available;
static bool trace_writeout_enabled;
-static TraceRecord trace_buf[TRACE_BUF_LEN];
+uint8_t trace_buf[TRACE_BUF_LEN];
static unsigned int trace_idx;
static FILE *trace_fp;
static char *trace_file_name = NULL;
+
/**
* Read a trace record from the trace buffer
*
@@ -75,16 +59,19 @@ 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)) {
+ TraceRecord *record = (TraceRecord *) &trace_buf[idx];
+ 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 */
+ memcpy(*recordptr, record, record->length);
+ (*recordptr)->event &= ~TRACE_RECORD_VALID;
return true;
}
@@ -106,6 +93,47 @@ static void flush_trace_file(bool wait)
g_static_mutex_unlock(&trace_lock);
}
+unsigned int trace_alloc_record(TraceEventID event, uint32_t datasize)
+{
+ unsigned int idx, rec_off;
+ uint32_t rec_len = ST_V2_REC_HDR_LEN + datasize;
+ uint64_t timestamp_ns = get_clock();
+
+ idx = g_atomic_int_exchange_and_add((gint *)&trace_idx, rec_len) %
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);
+ return idx;
+}
+
+void write_to_buffer(unsigned int idx, uint8_t *dataptr, uint32_t size)
+{
+ uint32_t x = 0;
+ while (x < size)
+ {
+ if (idx >= TRACE_BUF_LEN) {
+ idx = idx % TRACE_BUF_LEN;
+ }
+ trace_buf[idx++] = dataptr[x++];
+ }
+}
+
+void trace_mark_record_complete(unsigned int idx)
+{
+ TraceRecord *record = (TraceRecord*) &trace_buf[idx];
+
+ __sync_synchronize(); /* write barrier before marking as valid */
+ record->event |= TRACE_RECORD_VALID;
+
+ if (idx > TRACE_BUF_FLUSH_THRESHOLD) {
+ flush_trace_file(false);
+ }
+}
+
static void wait_for_trace_records_available(void)
{
g_static_mutex_lock(&trace_lock);
@@ -120,7 +148,7 @@ static void wait_for_trace_records_available(void)
static gpointer writeout_thread(gpointer opaque)
{
- TraceRecord record;
+ TraceRecord record, *recordptr;
unsigned int writeout_idx = 0;
unsigned int num_available, idx;
size_t unused __attribute__ ((unused));
@@ -130,19 +158,20 @@ static gpointer writeout_thread(gpointer opaque)
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);
+ record.event = DROPPED_EVENT_ID,
+ record.length = num_available,
+ unused = fwrite(&record, ST_V2_REC_HDR_LEN, 1, trace_fp);
writeout_idx += num_available;
}
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);
@@ -150,71 +179,7 @@ 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)
-{
- 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);
- }
-}
-
-void trace0(TraceEventID event)
-{
- trace(event, 0, 0, 0, 0, 0, 0);
-}
-
-void trace1(TraceEventID event, uint64_t x1)
-{
- trace(event, x1, 0, 0, 0, 0, 0);
-}
-
-void trace2(TraceEventID event, uint64_t x1, uint64_t x2)
-{
- trace(event, x1, x2, 0, 0, 0, 0);
-}
-void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3)
-{
- trace(event, x1, x2, x3, 0, 0, 0);
-}
-
-void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,
uint64_t x4)
-{
- trace(event, x1, x2, x3, x4, 0, 0);
-}
-
-void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,
uint64_t x4, uint64_t x5)
-{
- trace(event, x1, x2, x3, x4, x5, 0);
-}
-
-void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,
uint64_t x4, uint64_t x5, uint64_t x6)
-{
- trace(event, x1, x2, x3, x4, x5, x6);
-}
void st_set_trace_file_enabled(bool enable)
{
@@ -231,7 +196,7 @@ void st_set_trace_file_enabled(bool enable)
static const TraceRecord header = {
.event = HEADER_EVENT_ID,
.timestamp_ns = HEADER_MAGIC,
- .x1 = HEADER_VERSION,
+ .length = HEADER_VERSION,
};
trace_fp = fopen(trace_file_name, "wb");
@@ -288,23 +253,6 @@ 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..671cbeb 100644
--- a/trace/simple.h
+++ b/trace/simple.h
@@ -22,17 +22,34 @@ 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);
+/* Interfaces for simpletrace v2 */
+
+/** 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_V2_REC_HDR_LEN */
+} TraceRecord;
+
+#define ST_V2_REC_HDR_LEN 24
+
+enum {
+ TRACE_BUF_LEN = 4096 * 64,
+ TRACE_BUF_FLUSH_THRESHOLD = TRACE_BUF_LEN / 4,
+};
+
+extern uint8_t trace_buf[TRACE_BUF_LEN];
+
+unsigned int trace_alloc_record(TraceEventID event, uint32_t datasize);
+void write_to_buffer(unsigned int idx, uint8_t *dataptr, uint32_t size);
+void trace_mark_record_complete(unsigned int idx);
+
#endif /* TRACE_SIMPLE_H */
--
1.7.1.1
