From a7fdd30a22448f17e942436b9db2a94b48218eb6 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 5 Sep 2022 10:34:20 +0300 Subject: [PATCH] perf auxtrace: Add itrace option flag d+e to log on error 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 Reviewed-by: Namhyung Kim Signed-off-by: Adrian Hunter Cc: Ian Rogers Cc: Jiri Olsa Link: https://lore.kernel.org/r/20220905073424.3971-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/itrace.txt | 1 + tools/perf/Documentation/perf-config.txt | 7 +++++++ tools/perf/util/auxtrace.c | 13 +++++++++++++ tools/perf/util/auxtrace.h | 3 +++ 4 files changed, 24 insertions(+) diff --git a/tools/perf/Documentation/itrace.txt b/tools/perf/Documentation/itrace.txt index 6b18966..0916bbfe 100644 --- a/tools/perf/Documentation/itrace.txt +++ b/tools/perf/Documentation/itrace.txt @@ -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. diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt index 0420e71..39c890ea 100644 --- a/tools/perf/Documentation/perf-config.txt +++ b/tools/perf/Documentation/perf-config.txt @@ -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:: diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c index 6edab8a..b59c278 100644 --- a/tools/perf/util/auxtrace.c +++ b/tools/perf/util/auxtrace.c @@ -26,6 +26,7 @@ #include #include +#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; diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h index 6a4fbfd..cb8e0a0 100644 --- a/tools/perf/util/auxtrace.h +++ b/tools/perf/util/auxtrace.h @@ -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; }; /** -- 2.7.4