Date: Sun, 29 Aug 2010 12:17:47 GMT From: arundel@FreeBSD.org To: toby@apple.com, arundel@FreeBSD.org, freebsd-bugs@FreeBSD.org, arundel@FreeBSD.org Subject: Re: bin/86485: [patch] hexdump(1): hexdump -s speedup on /dev Message-ID: <201008291217.o7TCHlRi074042@freefall.freebsd.org>
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Synopsis: [patch] hexdump(1): hexdump -s speedup on /dev State-Changed-From-To: open->analyzed State-Changed-By: arundel State-Changed-When: Sun Aug 29 12:01:55 UTC 2010 State-Changed-Why: The cause for this issue is the use of getchar() which tests every character against EOF. This causes huge overhead as can be seen in this comparison between the BSD and Linux hexdump versions: FreeBSD: Linux: real 44,85 real 0.00 user 4,51 user 0.00 sys 38,76 sys 0.00 The command used for this was 'time -p hexdump -n 100 -s 1000000000 /dev/random'. Higher values for -s would simply take too much time on FreeBSD. ;) Responsible-Changed-From-To: freebsd-bugs->arundel Responsible-Changed-By: arundel Responsible-Changed-When: Sun Aug 29 12:01:55 UTC 2010 Responsible-Changed-Why: Assign to me. Although i don't have commit rights to src i'm working on this issue atm. http://www.freebsd.org/cgi/query-pr.cgi?pr=86485
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