From ad353b710c7493df3d4fc2d3a51819126bed2e81 Mon Sep 17 00:00:00 2001 From: Athira Rajeev Date: Tue, 18 Oct 2022 14:26:04 +0530 Subject: perf stat: Fix printing os->prefix in CSV metrics output 'perf stat' with CSV output option prints an extra empty string as first field in metrics output line. Sample output below: # ./perf stat -x, --per-socket -a -C 1 ls S0,1,1.78,msec,cpu-clock,1785146,100.00,0.973,CPUs utilized S0,1,26,,context-switches,1781750,100.00,0.015,M/sec S0,1,1,,cpu-migrations,1780526,100.00,0.561,K/sec S0,1,1,,page-faults,1779060,100.00,0.561,K/sec S0,1,875807,,cycles,1769826,100.00,0.491,GHz S0,1,85281,,stalled-cycles-frontend,1767512,100.00,9.74,frontend cycles idle S0,1,576839,,stalled-cycles-backend,1766260,100.00,65.86,backend cycles idle S0,1,288430,,instructions,1762246,100.00,0.33,insn per cycle ====> ,S0,1,,,,,,,2.00,stalled cycles per insn The above command line uses field separator as "," via "-x," option and per-socket option displays socket value as first field. But here the last line for "stalled cycles per insn" has "," in the beginning. Sample output using interval mode: # ./perf stat -I 1000 -x, --per-socket -a -C 1 ls 0.001813453,S0,1,1.87,msec,cpu-clock,1872052,100.00,0.002,CPUs utilized 0.001813453,S0,1,2,,context-switches,1868028,100.00,1.070,K/sec ------ 0.001813453,S0,1,85379,,instructions,1856754,100.00,0.32,insn per cycle ====> 0.001813453,,S0,1,,,,,,,1.34,stalled cycles per insn Above result also has an extra CSV separator after the timestamp. Patch addresses extra field separator in the beginning of the metric output line. The counter stats are displayed by function "perf_stat__print_shadow_stats" in code "util/stat-shadow.c". While printing the stats info for "stalled cycles per insn", function "new_line_csv" is used as new_line callback. The new_line_csv function has check for "os->prefix" and if prefix is not null, it will be printed along with cvs separator. Snippet from "new_line_csv": if (os->prefix) fprintf(os->fh, "%s%s", os->prefix, config->csv_sep); Here os->prefix gets printed followed by "," which is the cvs separator. The os->prefix is used in interval mode option ( -I ), to print time stamp on every new line. But prefix is already set to contain CSV separator when used in interval mode for CSV option. Reference: Function "static void print_interval" Snippet: sprintf(prefix, "%6lu.%09lu%s", ts->tv_sec, ts->tv_nsec, config->csv_sep); Also if prefix is not assigned (if not used with -I option), it gets set to empty string. Reference: function printout() in util/stat-display.c Snippet: .prefix = prefix ? prefix : "", Since prefix already set to contain cvs_sep in interval option, patch removes printing config->csv_sep in new_line_csv function to avoid printing extra field. After the patch: # ./perf stat -x, --per-socket -a -C 1 ls S0,1,2.04,msec,cpu-clock,2045202,100.00,1.013,CPUs utilized S0,1,2,,context-switches,2041444,100.00,979.289,/sec S0,1,0,,cpu-migrations,2040820,100.00,0.000,/sec S0,1,2,,page-faults,2040288,100.00,979.289,/sec S0,1,254589,,cycles,2036066,100.00,0.125,GHz S0,1,82481,,stalled-cycles-frontend,2032420,100.00,32.40,frontend cycles idle S0,1,113170,,stalled-cycles-backend,2031722,100.00,44.45,backend cycles idle S0,1,88766,,instructions,2030942,100.00,0.35,insn per cycle S0,1,,,,,,,1.27,stalled cycles per insn Fixes: 92a61f6412d3a09d ("perf stat: Implement CSV metrics output") Reported-by: Disha Goel Reviewed-By: Kajol Jain Signed-off-by: Athira Jajeev Tested-by: Disha Goel Cc: Andi Kleen Cc: Ian Rogers Cc: James Clark Cc: Jiri Olsa Cc: linuxppc-dev@lists.ozlabs.org Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Nageswara R Sastry Cc: Namhyung Kim Link: https://lore.kernel.org/r/20221018085605.63834-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/stat-display.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/perf/util') diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c index 9ba0f08582f0..ba66bb7fc1ca 100644 --- a/tools/perf/util/stat-display.c +++ b/tools/perf/util/stat-display.c @@ -273,7 +273,7 @@ static void new_line_csv(struct perf_stat_config *config, void *ctx) fputc('\n', os->fh); if (os->prefix) - fprintf(os->fh, "%s%s", os->prefix, config->csv_sep); + fprintf(os->fh, "%s", os->prefix); aggr_printout(config, os->evsel, os->id, os->nr); for (i = 0; i < os->nfields; i++) fputs(config->csv_sep, os->fh); -- cgit v1.2.3-59-g8ed1b