Article View: comp.os.linux.hardware
Article #875Re: SMP Performance?
From: Karl Heyes
Date: Tue, 05 Sep 2000 04:24
Date: Tue, 05 Sep 2000 04:24
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2962 bytes
In article <39B3E918.F02FA652@mail.com>, Beggar <cpegbeggar@mail.com> wrote: > Hi all, > > I want to ask what's the performance of SMP on Linux compare to Win NT/2000? > My application is mostly Java native thread that will spawn around 3-400 > threads. > > And I think that most of the CPU time in single CPU is waste in context > switching. Will SMP benefit in this case? > > How much should I expect will increase when using SMP in Linux?? Is it worth > for SMP or should I setup two mahines for load balancing?? > What you are asking is very vague, there are many issues wrt SMP. I'm not a guru on this, but some of the points that have been raised are. linux 2.2 is ok at the kernel level to 4 processors. linux 2.4 ok to 8 processors. This means nothing if your application doesn't use it effectively. WRT java, big issue, thread creation API is easy, many people think the one thread by client concept is ok, but it doesn't scale. You didn't state whether thats 400 running threads, either way under whatever OS, you will be hitting cache hard, and VM tricks (ie context switching) does have a penalty. I/O versus computation work. 8 processors doing image rendering sounds nice. linux does try to keep tasks on the same CPU, more cache hits that way, but if you ask 2 processors to schedule 300 jobs and each processor has 64k cache then whats the average share of the cache. Memory speed is slow to a CPU. karl.
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f798d,cc1da39e40a3e3e5,start X-Google-Attributes: gidf798d,public X-Google-Thread: 102b32,cc1da39e40a3e3e5,start X-Google-Attributes: gid102b32,public X-Google-Thread: 10669a,cc1da39e40a3e3e5,start X-Google-Attributes: gid10669a,public X-Google-Thread: 1103af,d94718a3a5387f28 X-Google-Attributes: gid1103af,public X-Google-ArrivalTime: 2000-09-08 21:20:07 PST Path: arc1-ca.pugleaf.net!supernews.google.com!sn-xit-02!10.10.220.73.MISMATCH!sn-xit-09!supernews.com!cyclone-sf.pbi.net!216.65.16.3!news-in.nibble.net!news.algonet.se!algonet!news-feed1.eu.concert.net!newsfeed.cwix.com!news.mind.net!news.chatlink.com!news-west.eli.net!sdd.hp.com!enews.sgi.com!news.tele.dk!193.190.198.17!newsfeeds.belnet.be!news.belnet.be!colt.net!diablo.theplanet.net!news.theplanet.net!newspost.theplanet.net!bogus!karl From: Karl Heyes <karl_heyes@removethisbit.lineone.net> Newsgroups: comp.os.linux.hardware,hk.comp.os.linux,comp.os.linux.misc,comp.os.linux.hardware,comp.os.linux.networking Subject: Re: SMP Performance? Date: Tue, 05 Sep 2000 04:24:15 +0000 Organization: Customer of Energis Squared Lines: 33 Message-ID: <8p1oru$3e5$1@news6.svr.pol.co.uk> References: <39B3E918.F02FA652@mail.com> NNTP-Posting-Host: modem-61.seagull.dialup.pol.co.uk X-Trace: news6.svr.pol.co.uk 968124094 3525 62.137.108.61 (5 Sep 2000 03:21:34 GMT) NNTP-Posting-Date: 5 Sep 2000 03:21:34 GMT X-Complaints-To: abuse@theplanet.net X-Newsreader: Pan 0.8.0