Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [tbench regression fixes]: digging out smelly deadmen. | Date | Sat, 25 Oct 2008 13:13:20 +0200 |
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On Saturday, 25 of October 2008, David Miller wrote: > From: "Rafael J. Wysocki" <rjw@sisk.pl> > Date: Sat, 25 Oct 2008 00:25:34 +0200 > > > On Friday, 10 of October 2008, Ingo Molnar wrote: > > > > > > * Evgeniy Polyakov <s0mbre@tservice.net.ru> wrote: > > > > > > > On Fri, Oct 10, 2008 at 01:42:45PM +0200, Ingo Molnar (mingo@elte.hu) wrote: > > > > > > vanilla 27: 347.222 > > > > > > no TSO/GSO: 357.331 > > > > > > no hrticks: 382.983 > > > > > > no balance: 389.802 > > > > > > > > > > okay. The target is 470 MB/sec, right? (Assuming the workload is sane > > > > > and 'fixing' it does not mean we have to schedule worse.) > > > > > > > > Well, that's where I started/stopped, so maybe we will even move > > > > further? :) > > > > > > that's the right attitude ;) > > > > Can anyone please tell me if there was any conclusion of this thread? > > I made some more analysis in private with Ingo and Peter Z. and found > that the tbench decreases correlate pretty much directly with the > ongoing increasing cpu cost of wake_up() and friends in the fair > scheduler. > > The largest increase in computational cost of wakeups came in 2.6.27 > when the hrtimer bits got added, it more than tripled the cost of a wakeup. > In 2.6.28-rc1 the hrtimer feature has been disabled, but I think that > should be backports into the 2.6.27-stable branch.
Thanks a lot for the info.
Could you please give me a pointer to the commit disabling the hrtimer feature?
Rafael
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