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Date: Tue, 26 Jan 2010 05:02:08 -0500 (EST) From: Justin Piszcz <jpiszcz@...idpixels.com> To: linux-kernel@...r.kernel.org Subject: Hyperthreading on Core i7s: To use or not to use? Hello, Should the 'correct' kernel [CPU] configuration for a core i7 860/870..? - Multi-core support - Cores: 8 - SMT: Enabled/ON >From CONFIG_SCHED_SMT: . SMT scheduler support improves the CPU scheduler's decision making . . when dealing with Intel Pentium 4 chips with HyperThreading at a . . cost of slightly increased overhead in some places. If unsure say . . N here. . Does this also 'help' and/or 'apply' as much when dealing with Core i7s? -- Quick little benchmark (pbzip2 -9 linux kernel source), the benchmark is really within the noise (8 on/off) - Multicore(8)/HT(Off) = 73.72user 0.33system 0:09.50elapsed 779%CPU (0avgtext+0avgdata 458528maxresident - Multicore(8)/HT(On) = 74.28user 0.40system 0:09.67elapsed 772%CPU (0avgtext+0avgdata 428304maxresident - Multicore(4)/HT(On) = 68.76user 0.30system 0:17.44elapsed 396%CPU (0avgtext+0avgdata 213616maxresident)k -- Has anyone done any in-depth benchmarking for the core i7s that have multiple cores and HT disabled/enabled? Justin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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