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Groups > linux.kernel > #1464920
| From | "H. Peter Anvin" <hpa@zytor.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [LKP] [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement |
| Date | 2016-08-18 06:00 +0200 |
| Message-ID | <s7mEO-2uu-15@gated-at.bofh.it> (permalink) |
| References | (2 earlier) <s6QbU-5V1-33@gated-at.bofh.it> <s6VOh-161-1@gated-at.bofh.it> <s71TH-5aR-1@gated-at.bofh.it> <s7hvs-7wd-15@gated-at.bofh.it> <s7mv8-2qJ-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On August 17, 2016 8:45:13 PM PDT, Borislav Petkov <bp@suse.de> wrote: >On Wed, Aug 17, 2016 at 03:29:04PM -0700, Huang, Ying wrote: >> branch-miss-rate decreased from ~0.30% to ~0.043%. >> >> So I guess there are some code alignment change, which caused >decreased >> branch miss rate. > >Hrrm, I still can't imagine how that would happen if the machine >supports POPCNT and we never call the __sw_hweight* variants. Or does >it? > >Can you paste /proc/cpuinfo from that Sandy Bridge-EP box? > >Thanks. popcnt was introduced in Nehalem AFAIK, two generations before Sandy Bridge. -- Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.
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Re: [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement "H. Peter Anvin" <hpa@zytor.com> - 2016-08-16 19:00 +0200
Re: [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement Borislav Petkov <bp@suse.de> - 2016-08-16 19:20 +0200
Re: [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement "H. Peter Anvin" <hpa@zytor.com> - 2016-08-17 01:20 +0200
Re: [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement Borislav Petkov <bp@suse.de> - 2016-08-17 07:50 +0200
Re: [LKP] [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement "Huang\, Ying" <ying.huang@intel.com> - 2016-08-18 00:30 +0200
Re: [LKP] [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement Borislav Petkov <bp@suse.de> - 2016-08-18 05:50 +0200
Re: [LKP] [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement "Huang\, Ying" <ying.huang@intel.com> - 2016-08-18 06:00 +0200
Re: [LKP] [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement Borislav Petkov <bp@suse.de> - 2016-08-18 06:20 +0200
Re: [LKP] [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement "H. Peter Anvin" <hpa@zytor.com> - 2016-08-18 06:00 +0200
Re: [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement Peter Zijlstra <peterz@infradead.org> - 2016-08-17 08:50 +0200
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