Date: Wed, 16 Mar 2011 21:48:13 +0100 From: Ivan Voras <ivoras@freebsd.org> To: Garrett Cooper <gcooper@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r219699 - head/sys/kern Message-ID: <AANLkTi=-0BFdeQUPOOc3tHxxOhPt17stq07CcyfZsDQq@mail.gmail.com> In-Reply-To: <AANLkTinOAWW%2B6a2WmhAjoqmj4V8aZkRHPJ%2BumVq=0onb@mail.gmail.com> References: <201103161622.p2GGMxNp097642@svn.freebsd.org> <20110316174642.GB6367@freebsd.org> <AANLkTika25WRx=TWJXeNg_2786U11ff7_O68DkBz1oKc@mail.gmail.com> <AANLkTiny%2Bgzdtc078Wm_dHC9AsNG_xMGeLkz_5U8iu8g@mail.gmail.com> <AANLkTinOAWW%2B6a2WmhAjoqmj4V8aZkRHPJ%2BumVq=0onb@mail.gmail.com>
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On 16 March 2011 21:37, Ivan Voras <ivoras@freebsd.org> wrote: > For now, there's a report (which actually inspired me to retest and > commit this) from someone who tried this on 2x 15k RPM SAS drives, > with much better results using read_max=128 (thread "gmirror > performance" on freebsd-fs@). I estimate that because his drives were > 15kRPM from the start, the improvement isn't as drastic going from 8 > to 128 as on these SATA drives I tested on (faster seeks). He went > from ~~ 195 MB/s to ~~ 258 MB/s while I go from ~~ 50 MB/s to ~~ 140 > MB/s. Btw I also tested that random IO isn't affected by this: it isn't. The read-ahead heuristics is working.
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