Re: Epic regression in throughput since v2.6.23

From: Ingo Molnar
Date: Sun Sep 13 2009 - 11:48:05 EST



* Serge Belyshev <belyshev@xxxxxxxxxxxxxxxxx> wrote:

> Note that the disabling NEW_FAIR_SLEEPERS doesn't fix 3%
> regression from v2.6.23, but instead makes "make -j4" runtime
> another 2% worse (27.05 -> 27.72).

ok - thanks for the numbers, will have a look.

> ---
> tools/perf/builtin-stat.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)

> + // quick ugly hack: if a "--" appears in the command, treat is as
> + // a delimiter and use remaining part as a "cleanup command",
> + // not affecting performance counters.
> + cleanup = cleanup_argc = 0;
> + for (j = 1; j < (argc-1); j ++) {
> + if (!strcmp (argv[j], "--")) {
> + cleanup = j + 1;
> + cleanup_argc = argc - j - 1;
> + argv[j] = NULL;
> + argc = j;
> + }
> + }

Nice feature!

How about doing it a bit cleaner, as '--repeat-prepare' and
'--repeat-cleanup' options, to allow both pre-repeat and post-repeat
cleanup ops to be done outside of the measured period?

Ingo
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