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Merge remote branch 'stefanha/tracing' into staging

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This commit is contained in:
Anthony Liguori 2011-03-11 08:03:55 -06:00
commit 98fa4a5932
8 changed files with 244 additions and 137 deletions
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2
block.c
View File

@ -2477,6 +2477,8 @@ BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs,
{
BlockDriver *drv = bs->drv;
trace_bdrv_aio_flush(bs, opaque);
if (bs->open_flags & BDRV_O_NO_FLUSH) {
return bdrv_aio_noop_em(bs, cb, opaque);
}

5
docs/tracing.txt
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@ -141,11 +141,6 @@ source tree. It may not be as powerful as platform-specific or third-party
trace backends but it is portable. This is the recommended trace backend
unless you have specific needs for more advanced backends.
Warning: the "simple" backend is not thread-safe so only enable trace events
that are executed while the global mutex is held. Much of QEMU meets this
requirement but some utility functions like qemu_malloc() or thread-related
code cannot be safely traced using the "simple" backend.
==== Monitor commands ====
* info trace

5
posix-aio-compat.c
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@ -455,6 +455,9 @@ static int posix_aio_process_queue(void *opaque)
} else {
ret = -ret;
}
trace_paio_complete(acb, acb->common.opaque, ret);
/* remove the request */
*pacb = acb->next;
/* call the callback */
@ -537,6 +540,8 @@ static void paio_cancel(BlockDriverAIOCB *blockacb)
struct qemu_paiocb *acb = (struct qemu_paiocb *)blockacb;
int active = 0;
trace_paio_cancel(acb, acb->common.opaque);
mutex_lock(&lock);
if (!acb->active) {
QTAILQ_REMOVE(&request_list, acb, node);

3
scripts/simpletrace.py
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@ -16,6 +16,7 @@ import inspect
header_event_id = 0xffffffffffffffff
header_magic = 0xf2b177cb0aa429b4
header_version = 0
dropped_event_id = 0xfffffffffffffffe
trace_fmt = '=QQQQQQQQ'
trace_len = struct.calcsize(trace_fmt)
@ -28,7 +29,7 @@ def parse_events(fobj):
"""Extract argument names from a parameter list."""
return tuple(arg.split()[-1].lstrip('*') for arg in args.split(','))
events = {}
events = {dropped_event_id: ('dropped', 'count')}
event_num = 0
for line in fobj:
m = event_re.match(line.strip())

339
simpletrace.c
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@ -12,6 +12,9 @@
#include <stdint.h>
#include <stdio.h>
#include <time.h>
#include <signal.h>
#include <pthread.h>
#include "qerror.h"
#include "qemu-timer.h"
#include "trace.h"
@ -24,6 +27,12 @@
/** Trace file version number, bump if format changes */
#define HEADER_VERSION 0
/** Records were dropped event ID */
#define DROPPED_EVENT_ID (~(uint64_t)0 - 1)
/** Trace record is valid */
#define TRACE_RECORD_VALID ((uint64_t)1 << 63)
/** Trace buffer entry */
typedef struct {
uint64_t event;
@ -37,126 +46,135 @@ typedef struct {
} TraceRecord;
enum {
TRACE_BUF_LEN = 64 * 1024 / sizeof(TraceRecord),
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.
*/
static pthread_mutex_t trace_lock = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t trace_available_cond = PTHREAD_COND_INITIALIZER;
static pthread_cond_t trace_empty_cond = PTHREAD_COND_INITIALIZER;
static bool trace_available;
static bool trace_writeout_enabled;
static TraceRecord trace_buf[TRACE_BUF_LEN];
static unsigned int trace_idx;
static FILE *trace_fp;
static char *trace_file_name = NULL;
static bool trace_file_enabled = false;
void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
{
stream_printf(stream, "Trace file \"%s\" %s.\n",
trace_file_name, trace_file_enabled ? "on" : "off");
}
static bool write_header(FILE *fp)
{
static const TraceRecord header = {
.event = HEADER_EVENT_ID,
.timestamp_ns = HEADER_MAGIC,
.x1 = HEADER_VERSION,
};
return fwrite(&header, sizeof header, 1, fp) == 1;
}
/**
* set_trace_file : To set the name of a trace file.
* @file : pointer to the name to be set.
* If NULL, set to the default name-<pid> set at config time.
* Read a trace record from the trace buffer
*
* @idx Trace buffer index
* @record Trace record to fill
*
* Returns false if the record is not valid.
*/
bool st_set_trace_file(const char *file)
static bool get_trace_record(unsigned int idx, TraceRecord *record)
{
st_set_trace_file_enabled(false);
free(trace_file_name);
if (!file) {
if (asprintf(&trace_file_name, CONFIG_TRACE_FILE, getpid()) < 0) {
trace_file_name = NULL;
return false;
}
} else {
if (asprintf(&trace_file_name, "%s", file) < 0) {
trace_file_name = NULL;
return false;
}
if (!(trace_buf[idx].event & TRACE_RECORD_VALID)) {
return false;
}
st_set_trace_file_enabled(true);
__sync_synchronize(); /* read memory barrier before accessing record */
*record = trace_buf[idx];
record->event &= ~TRACE_RECORD_VALID;
return true;
}
static void flush_trace_file(void)
/**
* Kick writeout thread
*
* @wait Whether to wait for writeout thread to complete
*/
static void flush_trace_file(bool wait)
{
/* If the trace file is not open yet, open it now */
if (!trace_fp) {
trace_fp = fopen(trace_file_name, "w");
if (!trace_fp) {
/* Avoid repeatedly trying to open file on failure */
trace_file_enabled = false;
return;
pthread_mutex_lock(&trace_lock);
trace_available = true;
pthread_cond_signal(&trace_available_cond);
if (wait) {
pthread_cond_wait(&trace_empty_cond, &trace_lock);
}
pthread_mutex_unlock(&trace_lock);
}
static void wait_for_trace_records_available(void)
{
pthread_mutex_lock(&trace_lock);
while (!(trace_available && trace_writeout_enabled)) {
pthread_cond_signal(&trace_empty_cond);
pthread_cond_wait(&trace_available_cond, &trace_lock);
}
trace_available = false;
pthread_mutex_unlock(&trace_lock);
}
static void *writeout_thread(void *opaque)
{
TraceRecord record;
unsigned int writeout_idx = 0;
unsigned int num_available, idx;
size_t 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;
}
write_header(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;
}
fflush(trace_fp);
}
if (trace_fp) {
size_t unused; /* for when fwrite(3) is declared warn_unused_result */
unused = fwrite(trace_buf, trace_idx * sizeof(trace_buf[0]), 1, trace_fp);
}
}
void st_flush_trace_buffer(void)
{
if (trace_file_enabled) {
flush_trace_file();
}
/* Discard written trace records */
trace_idx = 0;
}
void st_set_trace_file_enabled(bool enable)
{
if (enable == trace_file_enabled) {
return; /* no change */
}
/* Flush/discard trace buffer */
st_flush_trace_buffer();
/* To disable, close trace file */
if (!enable) {
fclose(trace_fp);
trace_fp = NULL;
}
trace_file_enabled = enable;
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)
{
TraceRecord *rec = &trace_buf[trace_idx];
unsigned int idx;
uint64_t timestamp;
if (!trace_list[event].state) {
return;
}
rec->event = event;
rec->timestamp_ns = get_clock();
rec->x1 = x1;
rec->x2 = x2;
rec->x3 = x3;
rec->x4 = x4;
rec->x5 = x5;
rec->x6 = x6;
timestamp = get_clock();
if (++trace_idx == TRACE_BUF_LEN) {
st_flush_trace_buffer();
idx = __sync_fetch_and_add(&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);
}
}
@ -195,24 +213,93 @@ void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t
trace(event, x1, x2, x3, x4, x5, x6);
}
/**
* Flush the trace buffer on exit
*/
static void __attribute__((constructor)) st_init(void)
void st_set_trace_file_enabled(bool enable)
{
atexit(st_flush_trace_buffer);
if (enable == !!trace_fp) {
return; /* no change */
}
/* Halt trace writeout */
flush_trace_file(true);
trace_writeout_enabled = false;
flush_trace_file(true);
if (enable) {
static const TraceRecord header = {
.event = HEADER_EVENT_ID,
.timestamp_ns = HEADER_MAGIC,
.x1 = HEADER_VERSION,
};
trace_fp = fopen(trace_file_name, "w");
if (!trace_fp) {
return;
}
if (fwrite(&header, sizeof header, 1, trace_fp) != 1) {
fclose(trace_fp);
trace_fp = NULL;
return;
}
/* Resume trace writeout */
trace_writeout_enabled = true;
flush_trace_file(false);
} else {
fclose(trace_fp);
trace_fp = NULL;
}
}
/**
* Set the name of a trace file
*
* @file The trace file name or NULL for the default name-<pid> set at
* config time
*/
bool st_set_trace_file(const char *file)
{
st_set_trace_file_enabled(false);
free(trace_file_name);
if (!file) {
if (asprintf(&trace_file_name, CONFIG_TRACE_FILE, getpid()) < 0) {
trace_file_name = NULL;
return false;
}
} else {
if (asprintf(&trace_file_name, "%s", file) < 0) {
trace_file_name = NULL;
return false;
}
}
st_set_trace_file_enabled(true);
return true;
}
void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
{
stream_printf(stream, "Trace file \"%s\" %s.\n",
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_idx; 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",
trace_buf[i].event, trace_buf[i].x1, trace_buf[i].x2,
trace_buf[i].x3, trace_buf[i].x4, trace_buf[i].x5,
trace_buf[i].x6);
record.event, record.x1, record.x2,
record.x3, record.x4, record.x5,
record.x6);
}
}
@ -226,30 +313,44 @@ void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, cons
}
}
static TraceEvent* find_trace_event_by_name(const char *tname)
bool st_change_trace_event_state(const char *name, bool enabled)
{
unsigned int i;
if (!tname) {
return NULL;
}
for (i = 0; i < NR_TRACE_EVENTS; i++) {
if (!strcmp(trace_list[i].tp_name, tname)) {
return &trace_list[i];
if (!strcmp(trace_list[i].tp_name, name)) {
trace_list[i].state = enabled;
return true;
}
}
return NULL; /* indicates end of list reached without a match */
}
bool st_change_trace_event_state(const char *tname, bool tstate)
{
TraceEvent *tp;
tp = find_trace_event_by_name(tname);
if (tp) {
tp->state = tstate;
return true;
}
return false;
}
void st_flush_trace_buffer(void)
{
flush_trace_file(true);
}
void st_init(const char *file)
{
pthread_t thread;
pthread_attr_t attr;
sigset_t set, oldset;
int ret;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
sigfillset(&set);
pthread_sigmask(SIG_SETMASK, &set, &oldset);
ret = pthread_create(&thread, &attr, writeout_thread, NULL);
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
if (ret != 0) {
error_report("warning: unable to create trace file thread\n");
return;
}
atexit(st_flush_trace_buffer);
st_set_trace_file(file);
}

8
simpletrace.h
View File

@ -15,6 +15,7 @@
#include <stdbool.h>
#include <stdio.h>
#ifdef CONFIG_SIMPLE_TRACE
typedef uint64_t TraceEventID;
typedef struct {
@ -36,5 +37,12 @@ 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);
void st_init(const char *file);
#else
static inline void st_init(const char *file)
{
/* Do nothing */
}
#endif /* !CONFIG_SIMPLE_TRACE */
#endif /* SIMPLETRACE_H */

3
trace-events
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@ -51,6 +51,7 @@ disable multiwrite_cb(void *mcb, int ret) "mcb %p ret %d"
disable bdrv_aio_multiwrite(void *mcb, int num_callbacks, int num_reqs) "mcb %p num_callbacks %d num_reqs %d"
disable bdrv_aio_multiwrite_earlyfail(void *mcb) "mcb %p"
disable bdrv_aio_multiwrite_latefail(void *mcb, int i) "mcb %p i %d"
disable bdrv_aio_flush(void *bs, void *opaque) "bs %p opaque %p"
disable bdrv_aio_readv(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d opaque %p"
disable bdrv_aio_writev(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d opaque %p"
@ -61,6 +62,8 @@ disable virtio_blk_handle_write(void *req, uint64_t sector, size_t nsectors) "re
# posix-aio-compat.c
disable paio_submit(void *acb, void *opaque, int64_t sector_num, int nb_sectors, int type) "acb %p opaque %p sector_num %"PRId64" nb_sectors %d type %d"
disable paio_complete(void *acb, void *opaque, int ret) "acb %p opaque %p ret %d"
disable paio_cancel(void *acb, void *opaque) "acb %p opaque %p"
# ioport.c
disable cpu_in(unsigned int addr, unsigned int val) "addr %#x value %u"

16
vl.c
View File

@ -47,9 +47,6 @@
#include <dirent.h>
#include <netdb.h>
#include <sys/select.h>
#ifdef CONFIG_SIMPLE_TRACE
#include "trace.h"
#endif
#ifdef CONFIG_BSD
#include <sys/stat.h>
@ -159,6 +156,7 @@ int main(int argc, char **argv)
#include "slirp/libslirp.h"
#include "trace.h"
#include "simpletrace.h"
#include "qemu-queue.h"
#include "cpus.h"
#include "arch_init.h"
@ -1941,10 +1939,8 @@ int main(int argc, char **argv, char **envp)
const char *incoming = NULL;
int show_vnc_port = 0;
int defconfig = 1;
#ifdef CONFIG_SIMPLE_TRACE
const char *trace_file = NULL;
#endif
atexit(qemu_run_exit_notifiers);
error_set_progname(argv[0]);
@ -2770,6 +2766,8 @@ int main(int argc, char **argv, char **envp)
}
loc_set_none();
st_init(trace_file);
/* If no data_dir is specified then try to find it relative to the
executable path. */
if (!data_dir) {
@ -2780,12 +2778,6 @@ int main(int argc, char **argv, char **envp)
data_dir = CONFIG_QEMU_DATADIR;
}
#ifdef CONFIG_SIMPLE_TRACE
/*
* Set the trace file name, if specified.
*/
st_set_trace_file(trace_file);
#endif
/*
* Default to max_cpus = smp_cpus, in case the user doesn't
* specify a max_cpus value.