Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83 (MC840302); site boring.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!mhuxn!mhuxr!ulysses!allegra!mit-eddie!think!harvard!seismo!mcvax!boring!jack From: jack@boring.UUCP Newsgroups: net.sources.bugs,net.unix-wizards Subject: Funny behaviour of bm under V7 Message-ID: <6591@boring.UUCP> Date: Wed, 21-Aug-85 15:37:47 EDT Article-I.D.: boring.6591 Posted: Wed Aug 21 15:37:47 1985 Date-Received: Sat, 24-Aug-85 17:15:22 EDT Reply-To: jack@mcvax.UUCP (Jack Jansen) Organization: AMOEBA project, CWI, Amsterdam Lines: 43 Xref: watmath net.sources.bugs:454 net.unix-wizards:14497 Apparently-To: rnews@mcvax.LOCAL I'm posting this to unix-wizards too, since I can't pin the problem on 'bm', so there might be something funny going on in the V7 kernel. I observed some very weird behaviour of the Boyer Moore program posted to net.sources recently. The problem is: user time is significantly less than that of grep, but system time is preposterous. Times are as follows, on an 11/34, running more-or-less v7m, 1Mb, Ampex Capricorn: --- + time bm Zurich /usr/dict/words Zurich real 1:00.0 user 3.5 sys 42.7 + time fgrep Zurich /usr/dict/words Zurich real 33.0 user 18.5 sys 6.6 + time grep Zurich /usr/dict/words Zurich real 22.0 user 11.2 sys 6.4 --- I tried fiddling with the buffer size being read (512,1024,2048), but timing stays the same. Also, profiling shows that the program spends 90% of the time in read(), so there are no other system calls that could account for the time difference. So, what is going on that's making bm 8 times slower than everyone else? Anyone out there who can give me a hint on where to look? -- Jack Jansen, jack@mcvax.UUCP The shell is my oyster.