Date: Thu, 29 Nov 2001 22:57:14 -0800 From: Peter Wemm <peter@wemm.org> To: rsharpe@ns.aus.com Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: A comparison of Samba performance on FreeBSD 4.3-RELEASE and Linux 2.4.13ac4 Message-ID: <20011130065714.B2C113808@overcee.netplex.com.au> In-Reply-To: <3C072706.2030501@ns.aus.com>
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Richard Sharpe wrote: > attached is a preliminary report on a comparison of Samba performance on > FreeBSD 4.3-RELEASE and Linux 2.4.13ac4. Are you aware that 4.3-RELEASE has IDE drive write caching turned off by default? What was the Linux system configured with? 4.4-RELEASE has it back on again by default. Secondly, are you using a GENERIC kernel or a tuned kernel? GENERIC is quite unrealistic these days due to supporting the lowest possible cpu (i386). There is a significant amount of overhead to support this. We really need to ship with a number of different kernels and install the best-match at install time. I have noticed that linux distributions have been doing this for quite some time, and even go as far as installing different libc's depending on cpu type. You mentioned using fsync() vs fdatasync(). fsync() is pretty much the worst possible thing that you can do to a softupdates file system as it effectively negates all benefits of the dependency tracking, but still incurs the significant expense of doing the tracking and unwinding. I would be curious to know what things looked like without fsync/fdatasync (on both sides for fairness), and with a freebsd non-softupdates filesystem mounted in async mode for parity with linux's async ext2fs. I can't say that I'm too suprised with the results though. It is fairly well known that Linux's network stack generally has lower latency, and the SMB request-response type protocol (is it still lockstep these days?) tends to make this visible. Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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