Date: Fri, 01 Jan 2010 22:47:12 +0000 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Pieter de Goeje <pieter@degoeje.nl> Cc: Alexander Motin <mav@freebsd.org>, freebsd-current@freebsd.org, Miroslav Lachman <000.fbsd@quip.cz>, Thomas Backman <serenity@exscape.org>, freebsd-arch@freebsd.org Subject: Re: File system blocks alignment Message-ID: <65036.1262386032@critter.freebsd.dk> In-Reply-To: Your message of "Fri, 01 Jan 2010 21:53:43 %2B0100." <201001012153.44349.pieter@degoeje.nl>
next in thread | previous in thread | raw e-mail | index | archive | help
In message <201001012153.44349.pieter@degoeje.nl>, Pieter de Goeje writes: >That yielded some pretty spectacular results. [...] > >Performance for restore was abysmal in the unaligned case, easily being 10 >times slower than aligned restore. Newfs was about 5 times as slow. That is what I expected, only I didn't expect a factor 14 in performance. I'm not surprised that newfs and restore take the biggest hits in that test, those are the hard ones, seen from the disk drive, all the read only work can be cached and "covered up" that way. Ideally, newfs/UFS should do a quick test to look for any obvious boundaries, and DTRT, a nice little task for somebody :-) Poul-Henning PS: The reason I asked for 3 iterations, was so we could calculate a standard deviation (See: ministat(8)) in order to have a statistical sound conclusion. With a factor 14 in time difference, I will for once conceede it unnecessary :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?65036.1262386032>