Date: Thu, 23 Sep 2010 13:10:03 GMT From: Alexander Motin <mav@FreeBSD.org> To: freebsd-acpi@FreeBSD.org Subject: Re: i386/135447: [i386] [request] Intel Core i7 and Nehalem-EP new features not supported Message-ID: <201009231310.o8NDA3rV041765@freefall.freebsd.org>
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The following reply was made to PR i386/135447; it has been noted by GNATS. From: Alexander Motin <mav@FreeBSD.org> To: Dmitry Kubov <dk@garant.ru> Cc: Andriy Gapon <avg@FreeBSD.org>, jh@FreeBSD.org, bug-followup <bug-followup@FreeBSD.org> Subject: Re: i386/135447: [i386] [request] Intel Core i7 and Nehalem-EP new features not supported Date: Thu, 23 Sep 2010 16:01:09 +0300 Dmitry Kubov wrote: > >> This CPU has only 266MHz TurboBoost speedup. And some part of it >> (probably half) could be enabled all the time. This benefit still could >> be overweighted by C-states latencies penalty. It could be interesting >> to test some other workloads, like compilation with different number of >> threads. >> > > Actually tested 8.1-RELEASE with both TurboBoost options in BIOS: > > TurboBoost OFF > Ubench Single CPU: 451935 (0.40s) > Ubench Single CPU: 450927 (0.40s) > Ubench Single CPU: 450486 (0.40s) > > TurboBoost ON > Ubench Single CPU: 450890 (0.40s) > Ubench Single CPU: 450890 (0.40s) > Ubench Single CPU: 449926 (0.40s) > > C-states latencies penalty is reasonable idea. But looks like P0-state > not activated at all. Try to kill powerd and manually set highest CPU frequency. 0.40s test time looks a bit suspicious, as powerd may just not react in time to set P0 state. > What about too high %% for C3 state during heavy load: > dev.cpu.0.cx_usage: 0.17% 0.06% 99.75% last 7560us It's not really strange. These numbers count number of enters into each state. So when CPU is completely bust - they won't be updated. Main case when C1 state should be actively used/counted is loads with high interrupt rate or heavy context switching, such as disk I/O or network load. >> Disk performance fix is reasonable. Some recent improvements in >> 9-CURRENT should improve it even more. What's about ubench - try some >> different load. >> > Can you suggest other CPU only benchmark? > > make -j 16 buildworld > can't load all cores, can't see less than 11% idle I think it's not the main goal to completely load all CPUs. But this test is realistic and has really usable result. -- Alexander Motin
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