Date: Tue, 31 Jul 2007 13:45:56 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Fluffles <etc@fluffles.net> Cc: geom@FreeBSD.org, Dominic Bishop <dom@bishnet.net> Subject: Re: Increasing GELI performance Message-ID: <20070731114555.GQ1092@garage.freebsd.pl> In-Reply-To: <46AE4B94.8010107@fluffles.net> References: <46AA50B4.9080901@fluffles.net> <20070727210032.0140413C457@mx1.freebsd.org> <20070730192654.GO1092@garage.freebsd.pl> <46AE4B94.8010107@fluffles.net>
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[-- Attachment #1 --] On Mon, Jul 30, 2007 at 10:35:32PM +0200, Fluffles wrote: > Pawel Jakub Dawidek wrote: > >No matter how many cores/cpus you have if you run single-threaded > >application. What you do exactly is: > >1. Send read of 128kB. > >2. One of geli threads picks it up, decrypts and sends it back. > >3. Send next read of 128kB. > >4. One of geli threads picks it up, decrypts and sends it back. > >... > > > >All threads will be used when there are more threads accessing provider. > > > > But isn't it true that the UFS filesystem utilizes read-ahead and with > that a multiple I/O queue depth (somewhere between 7 to 9 queued I/O's) > - even when using something like dd to sequentially read a file on a > mounted filesystem ? Then this read-ahead will cause multiple I/O > request coming in and geom_eli can use multiple threads to maximize I/O > throughput. Maybe Dominic can try playing with the "vfs.read_max" sysctl > variable. You are right in general, but if you reread e-mail I was answering to, you will see that the author was reading from/writing to GEOM provider, not file system. -- Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQFGryDzForvXbEpPzQRAgjpAKCMxdqXm0qNVI58S0TzWhusIsJoLwCaAy6P GUF5MHF9O83N+6ieA2Yo/N4= =rcFt -----END PGP SIGNATURE-----home | help
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