[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20090115094442.b6394544.akpm@linux-foundation.org>
Date: Thu, 15 Jan 2009 09:44:42 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: James Bottomley <James.Bottomley@...senPartnership.com>
Cc: Matthew Wilcox <matthew@....cx>,
"Wilcox, Matthew R" <matthew.r.wilcox@...el.com>,
chinang.ma@...el.com, linux-kernel@...r.kernel.org,
sharad.c.tripathi@...el.com, arjan@...ux.intel.com,
andi.kleen@...el.com, suresh.b.siddha@...el.com,
harita.chilukuri@...el.com, douglas.w.styner@...el.com,
peter.xihong.wang@...el.com, hubert.nueckel@...el.com,
chris.mason@...cle.com, srostedt@...hat.com,
linux-scsi@...r.kernel.org,
Andrew Vasquez <andrew.vasquez@...gic.com>,
Anirban Chakraborty <anirban.chakraborty@...gic.com>
Subject: Re: Mainline kernel OLTP performance update
On Thu, 15 Jan 2009 09:12:46 -0500 James Bottomley <James.Bottomley@...senPartnership.com> wrote:
> On Wed, 2009-01-14 at 18:04 -0800, Andrew Morton wrote:
> > On Wed, 14 Jan 2009 18:21:47 -0700 Matthew Wilcox <matthew@....cx> wrote:
> > > On Wed, Jan 14, 2009 at 04:35:57PM -0800, Andrew Morton wrote:
> > > > > > Linux OLTP Performance summary
> > > > > > Kernel# Speedup(x) Intr/s CtxSw/s us% sys% idle% iowait%
> > > > > > 2.6.24.2 1.000 21969 43425 76 24 0 0
> > > > > > 2.6.27.2 0.973 30402 43523 74 25 0 1
> > > > > > 2.6.29-rc1 0.965 30331 41970 74 26 0 0
> > >
> > > > But the interrupt rate went through the roof.
> > >
> > > Yes. I forget why that was; I'll have to dig through my archives for
> > > that.
> >
> > Oh. I'd have thought that this alone could account for 3.5%.
>
> Me too. Anecdotally, I haven't noticed this in my lab machines, but
> what I have noticed is on someone else's laptop (a hyperthreaded atom)
> that I was trying to demo powertop on was that IPI reschedule interrupts
> seem to be out of control ... they were ticking over at a really high
> rate and preventing the CPU from spending much time in the low C and P
> states. To me this implicates some scheduler problem since that's the
> primary producer of IPI reschedules ... I think it wouldn't be a
> significant extrapolation to predict that the scheduler might be the
> cause of the above problem as well.
>
Good point.
The context switch rate actually went down a bit.
I wonder if the Intel test people have records of /proc/interrupts for
the various kernel versions.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists