Date: Wed, 21 Dec 2011 08:46:04 +0100 From: Stefan Esser <se@freebsd.org> To: Ian Smith <smithi@nimnet.asn.au> Cc: Adrian Chadd <adrian@freebsd.org>, lev@freebsd.org, "Samuel J. Greear" <sjg@evilcode.net>, FreeBSD Stable Mailing List <freebsd-stable@freebsd.org>, "O. Hartmann" <ohartman@zedat.fu-berlin.de>, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: Benchmark (Phoronix): FreeBSD 9.0-RC2 vs. Oracle Linux 6.1 Server Message-ID: <4EF18EBC.9050103@freebsd.org> In-Reply-To: <20111220033328.I64681@sola.nimnet.asn.au> References: <4EE1EAFE.3070408@m5p.com> <CAJ-FndDniGH8QoT=kUxOQ%2BzdVhWF0Z0NKLU0PGS-Gt=BK6noWw@mail.gmail.com> <4EE2AE64.9060802@m5p.com> <4EE88343.2050302@m5p.com> <CAFHbX1%2B5PttyZuNnYot8emTn_AWkABdJCvnpo5rcRxVXj0ypJA@mail.gmail.com> <4EE933C6.4020209@zedat.fu-berlin.de> <CAPjTQNEJDE17TLH-mDrG_-_Qa9R5N3mSeXSYYWtqz_DFidzYQw@mail.gmail.com> <20111215024249.GA13557@icarus.home.lan> <4EE9A2A0.80607@zedat.fu-berlin.de> <CAJ-VmomWnAvsVPcK0mfFECvFw_FKcja1m3NE9ue=TOkF%2Bx14Xg@mail.gmail.com> <CANY-Wm8jbtr3tiwdGQMDx8SVZKEBspGwTV7Q0wziYWsV%2Bf3BSQ@mail.gmail.com> <6140271.20111219122721@serebryakov.spb.ru> <CANY-Wm9-JTN0gvjoRv4XFMDaweoPSoZ4erTUto3Z-s1LxqGzhg@mail.gmail.com> <20111220033328.I64681@sola.nimnet.asn.au>
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Am 21.12.2011 06:22, schrieb Ian Smith: > I find the results on this page very strange, but perhaps indicative: > > http://www.phoronix.com/scan.php?page=article&item=debian_kfreebsd_h210&num=1 > > Here we see scant difference in results between Debian running FreeBSD > 7.3 or 8.0 or Linux 2.6.32 kernels, yet native FreeBSD 7.3 and 8.0 > installations apparently run far slower, especially on the gzip test! You did not expect this, since all user space programs were compiled from identical sources, as were FreeBSD and kFreeBSD (probably with minimal deviations in kFreeBSD, which should not affect the results)? > Does this imply that given the similar kernel speed, Debian GNU userland > performs so dramatically better than FreeBSD userland? Or does it > perhaps point to the default tuning of the FreeBSD systems compared to > (here) Debian, for these particular tests? Indeed, `which gzip`? Well, the answer is quite simple: Just run the Linux binaries on FreeBSD or kFreeBSD (those compiled for testing Linux performance) and I'm convinced that you'll find that performance significantly improves. You did notice, that the 7-zip and gzip binaries were built with gcc-4.4.4 for Linux and with gcc-4.2.1 for FreeBSD? And another point: The relative advantage between FreeBSD and Linux is different on R52 and T61. Might it be the case that gcc-4.4.4 has better knowledge of the newer CPU in the latter (T61, Core 2 Duo) and optimizes for it, not for the CPU in the R52 (Pentium-M) anymore? And apparently 7-zip results are less affected by the compiler version than the gzip results. This also hints at the compiler as the reason for the better kFreeBSD and Linux results. (7-zip seems to be less dependent on the better optimization of the newer gcc, or it does not take as much advantage from it.) Funny is the finding, that gzip is measured slower on FreeBSD 7.3 than 8.0 on the Pentium-M, while it is faster on 7.3 on the Core 2 Duo. That does not match my expectations at all ... There are no technical reasons, that FreeBSD does not come with a newer GCC, as probably all in this list know. But OTOH, the newer GCC versions can easily be installed from a port or package, and thus it would not have been impossible to compare native binaries compiled with the same compiler version for all test cases. > And yes, FreeBSD could sure use some sort of tuning 'profiles' mechanism > to be able to preconfigure systems for at least several vastly different > types of workload. Nate Lawson used to talk about this, then in respect > to simple 'laptop vs desktop' scenarios, but we've since seen volumes > written, mostly in lists but some wikis, parts of the Handbook, guides > for performance tuning etc, scarcely accessible to J. Random Installer. > A set of tunings for these Phoronix benchmarks might be a good start? I doubt that tuning is responsible, because kFreeBSD performed better (with the test programs compiled with gcc-4.4.4). The benchmark measured just that, the better optimization of the newer gcc version. Install the port (perhaps an even later gcc version, gcc-4.5 is said to generate even better code than gcc-4.4) and make it the default compiler for ports, if you want to take advantage of the more advanced compiler. The FreeBSD ports system makes that very easy. BTW: Why don't we build binary packages with a later version of gcc than what is in the system. This should not cause any GPLv3 violation, and we could have the userland built with the compiler giving best performance ... Regards, Stefan
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