Comments on: SunSpider Statistics, Part II http://blog.mozilla.com/dmandelin/2009/02/06/sunspider-statistics-part-ii/ Just another Blog.mozilla.com weblog Fri, 20 Nov 2009 22:40:42 -0800 http://wordpress.org/?v=2.8.6 hourly 1 By: leo http://blog.mozilla.com/dmandelin/2009/02/06/sunspider-statistics-part-ii/comment-page-1/#comment-1091 leo Thu, 12 Feb 2009 00:42:05 +0000 http://blog.mozilla.com/dmandelin/?p=52#comment-1091 +1 for Bill's comment, and, on a more mundane level, just basic initialization costs. E.g., I'm using Cilk++ for some algorithm prototypes, and just starting the thread package takes 200ms, which blew out my initial benchmarks, and I got another 20ms of variance per job just for launching a task from bash that requests a pthread. +1 for Bill’s comment, and, on a more mundane level, just basic initialization costs.

E.g., I’m using Cilk++ for some algorithm prototypes, and just starting the thread package takes 200ms, which blew out my initial benchmarks, and I got another 20ms of variance per job just for launching a task from bash that requests a pthread.

]]> By: Bill McCloskey http://blog.mozilla.com/dmandelin/2009/02/06/sunspider-statistics-part-ii/comment-page-1/#comment-1085 Bill McCloskey Mon, 09 Feb 2009 07:31:02 +0000 http://blog.mozilla.com/dmandelin/?p=52#comment-1085 Hey Dave, this was really interesting. I love it when people really look into stuff like this. It'd be really interesting to isolate the sources of noise in these tests. Have you tried running the SunSpider tests at realtime priority? I know this is possible in Linux, and I imagine MacOS has a similar feature (in Linux you use sched_setscheduler). The upside is that you won't get interference from the scheduler or any other processes, so you just have to worry about the occasional interrupt bottom-half. The downside is that you'd better not have any infinite loops, or you'll have to reboot :-). Normally using RT prio isn't worth the aggravation, but since your tests are so short-running it might make sense. Hey Dave, this was really interesting. I love it when people really look into stuff like this. It’d be really interesting to isolate the sources of noise in these tests. Have you tried running the SunSpider tests at realtime priority? I know this is possible in Linux, and I imagine MacOS has a similar feature (in Linux you use sched_setscheduler). The upside is that you won’t get interference from the scheduler or any other processes, so you just have to worry about the occasional interrupt bottom-half. The downside is that you’d better not have any infinite loops, or you’ll have to reboot :-) . Normally using RT prio isn’t worth the aggravation, but since your tests are so short-running it might make sense.

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