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perf intel-pt: Support itrace option flag d+e to log on error 

Pass d+e option and log size via intel_pt_log_enable(). Allocate a buffer
for log messages and provide intel_pt_log_dump_buf() to dump and reset the
buffer upon decoder errors.

Example:

 $ sudo perf record -e intel_pt// sleep 1
 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.094 MB perf.data ]
 $ sudo perf config itrace.debug-log-buffer-size=300
 $ sudo perf script --itrace=ed+e+o | head -20
 Dumping debug log buffer (first line may be sliced)
                                         Other
           ffffffff96ca22f6:  48 89 e5                                        Other
           ffffffff96ca22f9:  65 48 8b 05 ff e0 38 69                         Other
           ffffffff96ca2301:  48 3d c0 a5 c1 98                               Other
           ffffffff96ca2307:  74 08                                           Jcc +8
           ffffffff96ca2311:  5d                                              Other
           ffffffff96ca2312:  c3                                              Ret
 ERROR: Bad RET compression (TNT=N) at 0xffffffff96ca2312
 End of debug log buffer dump
  instruction trace error type 1 time 15913.537143482 cpu 5 pid 36292 tid 36292 ip 0xffffffff96ca2312 code 6: Trace doesn't match instruction
 Dumping debug log buffer (first line may be sliced)
                                        Other
           ffffffff96ce7fe9:  f6 47 2e 20                                     Other
           ffffffff96ce7fed:  74 11                                           Jcc +17
           ffffffff96ce7fef:  48 8b 87 28 0a 00 00                            Other
           ffffffff96ce7ff6:  5d                                              Other
           ffffffff96ce7ff7:  48 8b 40 18                                     Other
           ffffffff96ce7ffb:  c3                                              Ret
 ERROR: Bad RET compression (TNT=N) at 0xffffffff96ce7ffb
 Warning:
 8 instruction trace errors

Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220905073424.3971-6-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2022-09-05 10:34:23 +03:00 committed by Arnaldo Carvalho de Melo
parent 50d7620b27
commit 65aee81afe
4 changed files with 117 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
tools/perf/Documentation/perf-intel-pt.txt
View File

@ -989,10 +989,13 @@ must be preceded by either '+' or '-'. The flags support by Intel PT are:
-a Suppress logging of perf events
+a Log all perf events
+e Output only on decoding errors (size configurable)
+o Output to stdout instead of "intel_pt.log"
By default, logged perf events are filtered by any specified time ranges, but
flag +a overrides that.
flag +a overrides that. The +e flag can be useful for analyzing errors. By
default, the log size in that case is 16384 bytes, but can be altered by
linkperf:perf-config[1] e.g. perf config itrace.debug-log-buffer-size=30000
In addition, the period of the "instructions" event can be specified. e.g.

94
tools/perf/util/intel-pt-decoder/intel-pt-log.c
View File

@ -5,12 +5,16 @@
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stdbool.h>
#include <string.h>
#include <linux/zalloc.h>
#include <linux/kernel.h>
#include "intel-pt-log.h"
#include "intel-pt-insn-decoder.h"
@ -18,18 +22,33 @@
#define MAX_LOG_NAME 256
#define DFLT_BUF_SZ (16 * 1024)
struct log_buf {
char *buf;
size_t buf_sz;
size_t head;
bool wrapped;
FILE *backend;
};
static FILE *f;
static char log_name[MAX_LOG_NAME];
bool intel_pt_enable_logging;
static bool intel_pt_dump_log_on_error;
static unsigned int intel_pt_log_on_error_size;
static struct log_buf log_buf;
void *intel_pt_log_fp(void)
{
return f;
}
void intel_pt_log_enable(void)
void intel_pt_log_enable(bool dump_log_on_error, unsigned int log_on_error_size)
{
intel_pt_enable_logging = true;
intel_pt_dump_log_on_error = dump_log_on_error;
intel_pt_log_on_error_size = log_on_error_size;
}
void intel_pt_log_disable(void)
@ -74,6 +93,77 @@ static void intel_pt_print_no_data(uint64_t pos, int indent)
fprintf(f, " ");
}
static ssize_t log_buf__write(void *cookie, const char *buf, size_t size)
{
struct log_buf *b = cookie;
size_t sz = size;
if (!b->buf)
return size;
while (sz) {
size_t space = b->buf_sz - b->head;
size_t n = min(space, sz);
memcpy(b->buf + b->head, buf, n);
sz -= n;
buf += n;
b->head += n;
if (sz && b->head >= b->buf_sz) {
b->head = 0;
b->wrapped = true;
}
}
return size;
}
static int log_buf__close(void *cookie)
{
struct log_buf *b = cookie;
zfree(&b->buf);
return 0;
}
static FILE *log_buf__open(struct log_buf *b, FILE *backend, unsigned int sz)
{
cookie_io_functions_t fns = {
.write = log_buf__write,
.close = log_buf__close,
};
FILE *file;
memset(b, 0, sizeof(*b));
b->buf_sz = sz;
b->buf = malloc(b->buf_sz);
b->backend = backend;
file = fopencookie(b, "a", fns);
if (!file)
zfree(&b->buf);
return file;
}
static void log_buf__dump(struct log_buf *b)
{
if (!b->buf)
return;
fflush(f);
fprintf(b->backend, "Dumping debug log buffer (first line may be sliced)\n");
if (b->wrapped)
fwrite(b->buf + b->head, b->buf_sz - b->head, 1, b->backend);
fwrite(b->buf, b->head, 1, b->backend);
fprintf(b->backend, "End of debug log buffer dump\n");
b->head = 0;
b->wrapped = false;
}
void intel_pt_log_dump_buf(void)
{
log_buf__dump(&log_buf);
}
static int intel_pt_log_open(void)
{
if (!intel_pt_enable_logging)
@ -86,6 +176,8 @@ static int intel_pt_log_open(void)
f = fopen(log_name, "w+");
else
f = stdout;
if (f && intel_pt_dump_log_on_error)
f = log_buf__open(&log_buf, f, intel_pt_log_on_error_size);
if (!f) {
intel_pt_enable_logging = false;
return -1;

3
tools/perf/util/intel-pt-decoder/intel-pt-log.h
View File

@ -14,9 +14,10 @@
struct intel_pt_pkt;
void *intel_pt_log_fp(void);
void intel_pt_log_enable(void);
void intel_pt_log_enable(bool dump_log_on_error, unsigned int log_on_error_size);
void intel_pt_log_disable(void);
void intel_pt_log_set_name(const char *name);
void intel_pt_log_dump_buf(void);
void __intel_pt_log_packet(const struct intel_pt_pkt *packet, int pkt_len,
uint64_t pos, const unsigned char *buf);

20
tools/perf/util/intel-pt.c
View File

@ -2419,6 +2419,8 @@ static int intel_pt_synth_error(struct intel_pt *pt, int code, int cpu,
pid_t pid, pid_t tid, u64 ip, u64 timestamp,
pid_t machine_pid, int vcpu)
{
bool dump_log_on_error = pt->synth_opts.log_plus_flags & AUXTRACE_LOG_FLG_ON_ERROR;
bool log_on_stdout = pt->synth_opts.log_plus_flags & AUXTRACE_LOG_FLG_USE_STDOUT;
union perf_event event;
char msg[MAX_AUXTRACE_ERROR_MSG];
int err;
@ -2438,6 +2440,16 @@ static int intel_pt_synth_error(struct intel_pt *pt, int code, int cpu,
code, cpu, pid, tid, ip, msg, timestamp,
machine_pid, vcpu);
if (intel_pt_enable_logging && !log_on_stdout) {
FILE *fp = intel_pt_log_fp();
if (fp)
perf_event__fprintf_auxtrace_error(&event, fp);
}
if (code != INTEL_PT_ERR_LOST && dump_log_on_error)
intel_pt_log_dump_buf();
err = perf_session__deliver_synth_event(pt->session, &event, NULL);
if (err)
pr_err("Intel Processor Trace: failed to deliver error event, error %d\n",
@ -4272,8 +4284,12 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
goto err_delete_thread;
}
if (pt->synth_opts.log)
intel_pt_log_enable();
if (pt->synth_opts.log) {
bool log_on_error = pt->synth_opts.log_plus_flags & AUXTRACE_LOG_FLG_ON_ERROR;
unsigned int log_on_error_size = pt->synth_opts.log_on_error_size;
intel_pt_log_enable(log_on_error, log_on_error_size);
}
/* Maximum non-turbo ratio is TSC freq / 100 MHz */
if (pt->tc.time_mult) {