On Wed, 14 Jan 2009 21:14:35 +0100 Ingo Molnar <mingo@xxxxxxx> wrote: > > * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > On Wed, 14 Jan 2009 20:00:08 +0100 > > Ingo Molnar <mingo@xxxxxxx> wrote: > > > > > > > > * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > On Wed, 14 Jan 2009 19:33:19 +0100 Ingo Molnar <mingo@xxxxxxx> wrote: > > > > > > > > > Please pull the adaptive-mutexes-for-linus git tree > > > > > > > > <fear> > > > > > > > > - It seems a major shortcoming that the feature is disabled if > > > > CONFIG_DEBUG_MUTEXES=y. It means that lots of people won't test it. > > > > ^^^? > > > > > > - When people hit performance/latency oddities, it would be nice if > > > > they had a /proc knob with which they could disable this feature at > > > > runtime. > > > > > > > > This would also be useful for comparative performance testing. > > > > > > Yeah. From my other mail: > > > > > > > > We still have the /sys/debug/sched_features tunable under > > > > > CONFIG_SCHED_DEBUG=y, so should this cause any performance regressions > > > > > somewhere, it can be pinned down and blamed back on this change > > > > > easily, without bisection and without rebooting the box. > > > > > > This kind of easy knob was included early on - this is how all those spin > > > versus no-spin numbers were done. > > > > Do people enable CONFIG_SCHED_DEBUG? > > If they suspect performance problems and want to analyze them? The vast majority of users do not and usually cannot compile their own kernels. > Note that CONFIG_SCHED_DEBUG=y is also the default. akpm:/usr/src/25> echo $ARCH x86_64 akpm:/usr/src/25> make defconfig *** Default configuration is based on 'x86_64_defconfig' # # configuration written to .config # akpm:/usr/src/25> grep SCHED_DEBUG .config # CONFIG_SCHED_DEBUG is not set > > CONFIG_DEBUG_MUTEXES=n, CONFIG_SCHED_DEBUG=y is getting to be a pretty > > small subset? > > Those two are the default config settings actually, so i'd expect it to be > the most commonly occuring combinations. akpm:/usr/src/25> grep DEBUG_MUTEXES .config # CONFIG_DEBUG_MUTEXES is not set -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
