On Fri, 28 Sep 2007 20:48:59 +0200 Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote: > > On Fri, 2007-09-28 at 11:49 -0700, Andrew Morton wrote: > > > Do you know where the stalls are occurring? throttle_vm_writeout(), or via > > direct calls to congestion_wait() from page_alloc.c and vmscan.c? (running > > sysrq-w five or ten times will probably be enough to determine this) > > would it make sense to instrument congestion_wait() callsites with > vmstats? Better than nothing, but it isn't a great fit: we'd need one vmstat counter per congestion_wait() callsite, and it's all rather specific to the kernel-of-the-day. taskstats delay accounting isn't useful either - it will aggregate all the schedule() callsites. profile=sleep is just about ideal for this, isn't it? I suspect that most people don't know it's there, or forgot about it. It could be that profile=sleep just tells us "you're spending a lot of time in io_schedule()" or congestion_wait(), so perhaps we need to teach it to go for walk up the stack somehow. But lockdep knows how to do that already so perhaps we (ie: you ;)) can bolt sleep instrumentation onto lockdep as we (ie you ;)) did with the lockstat stuff? (Searches for the lockstat documentation) Did we forget to do that? _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
