Date: Thu, 7 Oct 2004 15:33:48 -0700 From: Kris Kennaway <kris@obsecurity.org> To: TM4525@aol.com Cc: drosih@rpi.edu Subject: Re: What version of FBSD does Yahoo run? Message-ID: <20041007223348.GA22413@xor.obsecurity.org> In-Reply-To: <15b.40fefe13.2e971096@aol.com> References: <15b.40fefe13.2e971096@aol.com>
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--8t9RHnE3ZwKMSgU+ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 07, 2004 at 05:35:18PM -0400, TM4525@aol.com wrote: > In a message dated 10/7/04 4:06:34 PM Eastern Daylight Time, drosih@rpi.e= du=20 > writes: > Here's one benchmark, showing UDP packet/second generation > rate from userland on a dual xeon machine under various > target loads: >=20 > Desired Optimal 5.x-UP 5.x-SMP 4.x-UP 4.x-SMP > 50000 50000 50000 50000 50000 50000 > 75000 75000 75001 75001 75001 75001 > 100000 100000 100000 100000 100000 100000 > 125000 125000 125000 125000 125000 125000 > 150000 150000 150015 150014 150015 150015 > 175000 175000 175008 175008 175008 169097 > 200000 200000 200000 179621 181445 169451 > 225000 225000 225022 179729 181367 169831 > 250000 250000 242742 179979 181138 169212 > 275000 275000 242102 180171 181134 169283 > 300000 300000 242213 179157 181098 169355 >=20 > That does show results for both single-processor (5.x-UP 4.x-UP) > and multi- processor (5.x-SMP, 4.x-SMP) benchmarks. It may be > that he ignored the table as soon as he read "dual Xeon". > -------------------------------------------- > I haven't seen this before. Check your email..the above was copied from an email of mine in this thread from earlier today. > If I did, I would immediately ask: >=20 > - What is the control here? What does your "benchmark" test? UDP packet generation rate from userland. > - Is this on a gigabit link? What are the packet sizes? Was network > availability a factor in limiting the test results? I didn't run that benchmark myself, so I'm not the best person to answer all of your questions, and I've asked the person who did to comment in more detail. > - What does "target load" mean? Does it mean don't try to send > more than that? If so, what does it show if you reach it? If you=20 > don't measure the utilization that it takes to saturate your "target" > I don't see the point of having it. > > - It seems that the only thing you could learn from this test would=20 > be what is the maximum pps > you could achieve unidirectionally out of a system. Why is that > useful, since its hardly ever the requirement unless you're=20 > building a traffic generator? You can see from the data that 5.x systems are capable of pushing out more packets from userland than 4.x systems are. That's an aspect of kernel performance, and it's one that's relevant for a number of applications involving high data-rate transmission from userland. If that's not what you're interested in, then you can go and run your own benchmarks and let us know what you find out. > - a relatively slow machine (a 1.7Ghz celeron with a 32-bit/33mhz > fxp NIC running 4.9) pushes over 250Kpps, so why is your machine,=20 > with seemingly superior hardware, so slow? Because traffic is being generated from userland, not from within the kernel. > Assuming that your benchmark does test something, Your "results" > seem to show that a uniprocessor machine is substantially more > efficient than an SMP box. For this workload, yes. > It also seems that the gap has widened between UP and SMP > performance in 5.x. Wasn't one of the goals of 5.x to substantially > improve SMP performance? Yes, and it's ongoing. You don't see it on this workload, but there are other benchmarks (e.g. mysql select testing) that I don't have to hand at the moment, which show the smp benefits of 5.3 more clearly. > This seems to show the opposite. No, it shows a small increase on SMP and a large increase on UP. Anyway, weren't you demanding an email ago that I produce benchmarks on UP systems, because no-one really uses SMP? Kris --8t9RHnE3ZwKMSgU+ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBZcRLWry0BWjoQKURArKVAKDdYkpLi0W+DnaOQHWtGjyYbFxilwCcCzEd K3QHWmkQkT48vNuiR0UdxZk= =XthH -----END PGP SIGNATURE----- --8t9RHnE3ZwKMSgU+--
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