Date: Sat, 11 Feb 2006 00:55:16 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: Poul-Henning Kamp <phk@phk.freebsd.dk>, current@freebsd.org Subject: Re: [TEST/REVIEW] cpu time accounting patch, step 2 Message-ID: <20060211005438.E90460@fledge.watson.org> In-Reply-To: <17388.60202.862312.337026@grasshopper.cs.duke.edu> References: <17388.44976.250463.383429@grasshopper.cs.duke.edu> <5383.1139586916@critter.freebsd.dk> <17388.60202.862312.337026@grasshopper.cs.duke.edu>
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On Fri, 10 Feb 2006, Andrew Gallatin wrote: > Unfortunately, even after your patch, we are still about 38% slower than > linux x86_64 on the same box for loopback ping-pong, and 32% slower for > ping-pong over 10GbE. (bandwidth is lower for streaming tests, and CPU > utilization is much, much much higher in FreeBSD as well). > > I think you nailed the biggest source of overhead, but there is apparently a > lot more performance that we can get out of the hardware. I'd love to see > you commit this. I can't remember if I pointed you at this before, but I remember us talking about it by e-mail. What happens to your loopback performance if you compile PREEMPTION out of the kernel? Robert N M Watson > > Drew > > x loopback_rr.after > + loopback_rr.rhel4 > +--------------------------------------------------------------------------+ > | x + | > |x x xx + ++ +| > | |_MA__| |_AM_|| > +--------------------------------------------------------------------------+ > N Min Max Median Avg Stddev > x 5 38590.71 40167.44 39301.22 39463.23 645.1375 > + 5 53349.28 54884.98 54388.49 54274.174 566.90395 > Difference at 95.0% confidence > 14810.9 +/- 885.686 > 37.531% +/- 2.24433% > (Student's t, pooled s = 607.282) > > > x 10GbE_rr.after > + 10GbE_rr.rhel4 > +--------------------------------------------------------------------------+ > | x + | > |xxx + + + +| > | AM |___A_M_|| > +--------------------------------------------------------------------------+ > N Min Max Median Avg Stddev > x 6 33323.05 33703.95 33614.14 33556.268 137.33838 > + 5 43448.3 44966.41 44610.41 44331.738 606.53307 > Difference at 95.0% confidence > 10775.5 +/- 571.321 > 32.1116% +/- 1.70258% > (Student's t, pooled s = 417.112) > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >
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