Date: Fri, 11 Mar 2005 19:37:12 -0500 From: Tom Rhodes <trhodes@FreeBSD.org> To: Nate Lawson <njl@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/fs/msdosfs msdosfs_conv.c Message-ID: <20050311193712.236d804a@mobile.pittgoth.com> In-Reply-To: <200503112327.j2BNRkGq052260@repoman.freebsd.org> References: <200503112327.j2BNRkGq052260@repoman.freebsd.org>
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On Fri, 11 Mar 2005 23:27:46 +0000 (UTC) Nate Lawson <njl@FreeBSD.org> wrote: > njl 2005-03-11 23:27:46 UTC > > FreeBSD src repository > > Modified files: > sys/fs/msdosfs msdosfs_conv.c > Log: > The mbnambuf routines combine multiple substrings into a single > long filename. Each substring is indexed by the windows ID, a > sequential one-based value. The previous code was extremely slow, > doing a malloc/strcpy/free for each substring. > > This code optimizes these routines with this in mind, using the ID > to index into a single array and concatenating each WIN_CHARS chunk > at once. (The last chunk is variable-length.) > > This code has been tested as working on an FS with difficult filename > sizes (255, 13, 26, etc.) It gives a 77.1% decrease in profiled > time (total across all functions) and a 73.7% decrease in wall time. > Test was "ls -laR > /dev/null". > > Per-function time savings: > mbnambuf_init: -90.7% > mbnambuf_write: -18.7% > mbnambuf_flush: -67.1% > > MFC after: 1 month > > Revision Changes Path > 1.40 +42 -37 src/sys/fs/msdosfs/msdosfs_conv.c > That's hot. :) -- Tom Rhodes
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