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Nick Piggin wrote: > Rik van Riel wrote:> >> Lorenzo Allegrucci wrote:>>>>> Hi lkml,>>>>>> according to the test below (sysbench) Linux seems to have scalability >>> problems beyond 8 client threads:>>> http://jeffr-tech.livejournal.com/6268.html#cutid1>>> http://jeffr-tech.livejournal.com/5705.html>>> Hardware is an 8-core amd64 system and jeffr seems willing to try more >>> Linux versions on that machine.>>> Anyway, is there anyone who can reproduce this?>>>>>>>> I have reproduced it on a quad core test system.>>>> With 4 threads (on 4 cores) I get a high throughput, with >> approximately 58% user time and 42% system time.>>>> With 8 threads (on 4 cores) I get way lower throughput, >> with 37% user time, 29% system time 35% idle time!>>>> The maximum time taken per query also increases from >> 0.0096s to 0.5273s. Ouch!>>>> I don't know if this is MySQL, glibc or Linux kernel, >> but something strange is going on...> > > Like you, I'm also seeing idle time start going up as threads increase. > > I initially thought this was a problem with the multiprocessor scheduler, > because the pattern is exactly like some artificat in the load balancing. "artificat" Wow. I must need some sleep :) Please excuse any other typos! -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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