Date: Tue, 10 Dec 1996 21:17:26 -0800 (PST) From: John Dyson <dyson> To: CVS-committers, cvs-all, cvs-sys Subject: cvs commit: src/sys/ufs/ufs ufs_readwrite.c Message-ID: <199612110517.VAA14335@freefall.freebsd.org>
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dyson 96/12/10 21:17:25 Modified: sys/ufs/ufs ufs_readwrite.c Log: Significant performance improvement for mmap'ed files. This commit makes MADV_SEQUENTIAL much more effective. I suggest that we start using MADV_SEQUENTIAL on system utilities that mmap their input files, and the I/O is predominantely sequential. Below is a test with 'cmp' on two relatively large binary files, where the files are so large that the caching is ineffective: + ls -l t1.xxx t2.xxx -rw-r--r-- 1 root wheel 65598384 Dec 10 12:13 t1.xxx -rw-r--r-- 1 root wheel 65598384 Dec 10 12:14 t2.xxx + time cmp t1.xxx t2.xxx 3.78user 0.70system 1:33.43elapsed 4%CPU + time cmpmadv t1.xxx t2.xxx 4.21user 1.05system 0:30.93elapsed 17%CPU This change is as a result of an observation made by BDE. Revision Changes Path 1.23 +41 -1 src/sys/ufs/ufs/ufs_readwrite.c
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