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perf auxtrace: Add itrace option flag d+e to log on error

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Add flag +e to the itrace d (decoder debug log) option to get output only
on decoding errors.

The log can be very big so reducing the output to where there are decoding
errors can be useful for analyzing errors.

By default, the log size in that case is 16384 bytes, but can be altered by
perf config e.g. perf config itrace.debug-log-buffer-size=30000

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/20220905073424.3971-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2022-09-05 10:34:20 +03:00 committed by Arnaldo Carvalho de Melo
parent c3ca8d4418
commit a7fdd30a22
4 changed files with 24 additions and 0 deletions
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1
tools/perf/Documentation/itrace.txt
View file

@ -64,6 +64,7 @@
debug messages will or will not be logged. Each flag must be preceded
by either '+' or '-'. The flags are:
a all perf events
e output only on errors (size configurable - see linkperf:perf-config[1])
o output to stdout
If supported, the 'q' option may be repeated to increase the effect.

7
tools/perf/Documentation/perf-config.txt
View file

@ -729,6 +729,13 @@ auxtrace.*::
If the directory does not exist or has the wrong file type,
the current directory is used.
itrace.*::
debug-log-buffer-size::
Log size in bytes to output when using the option --itrace=d+e
Refer 'itrace' option of linkperf:perf-script[1] or
linkperf:perf-report[1]. The default is 16384.
daemon.*::
daemon.base::

13
tools/perf/util/auxtrace.c
View file

@ -26,6 +26,7 @@
#include <linux/list.h>
#include <linux/zalloc.h>
#include "config.h"
#include "evlist.h"
#include "dso.h"
#include "map.h"
@ -1434,6 +1435,16 @@ static int get_flags(const char **ptr, unsigned int *plus_flags, unsigned int *m
}
}
#define ITRACE_DFLT_LOG_ON_ERROR_SZ 16384
static unsigned int itrace_log_on_error_size(void)
{
unsigned int sz = 0;
perf_config_scan("itrace.debug-log-buffer-size", "%u", &sz);
return sz ?: ITRACE_DFLT_LOG_ON_ERROR_SZ;
}
/*
* Please check tools/perf/Documentation/perf-script.txt for information
* about the options parsed here, which is introduced after this cset,
@ -1532,6 +1543,8 @@ int itrace_do_parse_synth_opts(struct itrace_synth_opts *synth_opts,
if (get_flags(&p, &synth_opts->log_plus_flags,
&synth_opts->log_minus_flags))
goto out_err;
if (synth_opts->log_plus_flags & AUXTRACE_LOG_FLG_ON_ERROR)
synth_opts->log_on_error_size = itrace_log_on_error_size();
break;
case 'c':
synth_opts->branches = true;

3
tools/perf/util/auxtrace.h
View file

@ -60,6 +60,7 @@ enum itrace_period_type {
#define AUXTRACE_ERR_FLG_DATA_LOST (1 << ('l' - 'a'))
#define AUXTRACE_LOG_FLG_ALL_PERF_EVTS (1 << ('a' - 'a'))
#define AUXTRACE_LOG_FLG_ON_ERROR (1 << ('e' - 'a'))
#define AUXTRACE_LOG_FLG_USE_STDOUT (1 << ('o' - 'a'))
/**
@ -110,6 +111,7 @@ enum itrace_period_type {
* @log_plus_flags: flags to affect what is logged
* @log_minus_flags: flags to affect what is logged
* @quick: quicker (less detailed) decoding
* @log_on_error_size: size of log to keep for outputting log only on errors
*/
struct itrace_synth_opts {
bool set;
@ -155,6 +157,7 @@ struct itrace_synth_opts {
unsigned int log_plus_flags;
unsigned int log_minus_flags;
unsigned int quick;
unsigned int log_on_error_size;
};
/**