Date: Fri, 21 Dec 2007 00:51:33 +0100 From: Peter Schuller <peter.schuller@infidyne.com> To: Julian Elischer <julian@elischer.org> Cc: freebsd-fs@freebsd.org, ticso@cicely.de, Ivan Voras <ivoras@freebsd.org> Subject: Re: readv: parallel or sequential? Message-ID: <200712210051.41936.peter.schuller@infidyne.com> In-Reply-To: <476AFDBC.9040301@elischer.org> References: <fjbb3v$n60$1@ger.gmane.org> <200712210036.49040.peter.schuller@infidyne.com> <476AFDBC.9040301@elischer.org>
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[-- Attachment #1 --] > multiple reads and writes to the same file *From different file > descriptors* (same process or not) might proceed in "parallel" but readv > and writev will be implemented serially to the filesystem. now IF THE > FILESYSTEM IS NOT DOING SYNCHRONOUS DISK ACCESSES the reads and writes > might proceed in parallel or be grouped, clustered or otherwise rearanged. If the original claims were just as applied to readv/writev, I don't really have a problem since there is no guarantee that it will be performed in parallel (though even then, assuming non-synchronous writes, it would certainly be nice if it did pass it along to the device layer in a fashion that allowed concurrency). But when I/O is clearly being done with the intent of concurrency (by using AIO or by performing the I/O in different threads/processes), it is more important. -- / Peter Schuller PGP userID: 0xE9758B7D or 'Peter Schuller <peter.schuller@infidyne.com>' Key retrieval: Send an E-Mail to getpgpkey@scode.org E-Mail: peter.schuller@infidyne.com Web: http://www.scode.org [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBHawANDNor2+l1i30RApKtAJ42aWOvXKnYbC73AoXaZvza/I1MVwCdFei1 0FAfRm9x1swgNtx3YDTVmww= =NQ+4 -----END PGP SIGNATURE-----help
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