Date: Wed, 20 Mar 2002 09:58:02 -0800 (PST) From: David Malone <dwmalone@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/ufs/ufs ufs_dirhash.c Message-ID: <200203201758.g2KHw2o36141@freefall.freebsd.org>
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dwmalone 2002/03/20 09:58:02 PST
Modified files:
sys/ufs/ufs ufs_dirhash.c
Log:
Two minor changes to dirhash, which result in some marginal benchmark
improvements.
1) If deleting an entry results in a chain of deleted slots ending in an
empty slot, then we can be a bit more aggressive about marking slots as
empty.
2) The last stage of the FNV hash is to xor the last byte of data
into the hash. This means that filenames which differ only in
the last byte will be placed close to one another in the hash
table, which forms longer chains. To work around this common
case, we also hash in the address of the dirhash structure.
news/cancel = news/articles/control/cancel for a tradspool inn server
squid2 = squid level 2 directory (dirs called 00->FF)
squid3 = squid level 3 directory (files called 00001F00->00001FFF)
mean #probes for
home dir mh inbox news/cancel tmp squid2 squid3
old successful 1.02 3.19 4.07 1.10 7.85 2.06
new successful 1.04 1.32 1.27 1.04 1.93 1.17
old unsuccessful 1.08 4.50 5.37 1.17 10.76 2.69
new unsuccessful 1.08 1.73 1.64 1.17 2.89 1.37
Reviewed by: iedowse
MFC after: 2 weeks
Revision Changes Path
1.10 +15 -3 src/sys/ufs/ufs/ufs_dirhash.c
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