On Thu, 15 Jan 2009 09:12:46 -0500 James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> 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@xxxxxx> 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-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
