Date: Tue, 14 Apr 1998 16:59:40 +0200 From: Frank Ederveen <frank@our.domaintje.com> To: tarkhil@asteroid.svib.ru, hackers@FreeBSD.ORG Cc: smp@FreeBSD.ORG Subject: Re: SMP performance decrease? Message-ID: <19980414165940.06093@domaintje.com> In-Reply-To: <199804141149.PAA19398@asteroid.svib.ru>; from Alexander B. Povolotsky on Tue, Apr 14, 1998 at 03:49:35PM %2B0400 References: <199804141149.PAA19398@asteroid.svib.ru>
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On Tue, Apr 14, 1998 at 03:49:35PM +0400, Alexander B. Povolotsky wrote: > Here are the results: > > Test Non-SMP SMP > arith (double) 27.5 28.1 > Drystone 2 (no reg. vars) 23.6 24.1 > Execl thoughput 90.8 46.8 <- ??? > File copy 35.1 37.7 > Pipe-based context switching 20.4 9.0 <- ??? > Shell scripts (8 concurrent) 12.8 12.2 <- ??? > > I don't understand why execl throughput and context switching is TWICE > slower in SMP mode, and I doesn't understand AT ALL why shell script > benchmark isn't twice faster. I don't know Benchbyte, but maybe these are times in seconds and lower is better? Also, unless you have an automatic multi threading compiler like Convex has the second cpu doesn't do you much good if you only run one process in your benchmark. Try making a kernel or buildworld with -j 2 in single and dual cpu mode? Regards, FrankE To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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