From: Andrea Arcangeli <aarcange@redhat.com> To: Linus Torvalds <torvalds@linux-foundation.org> Cc: ying.huang@intel.com, Michal Hocko <mhocko@suse.com>, s.priebe@profihost.ag, mgorman@techsingularity.net, Linux List Kernel Mailing <linux-kernel@vger.kernel.org>, alex.williamson@redhat.com, lkp@01.org, rientjes@google.com, kirill@shutemov.name, Andrew Morton <akpm@linux-foundation.org>, zi.yan@cs.rutgers.edu, Vlastimil Babka <vbabka@suse.cz> Subject: Re: [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression Date: Wed, 28 Nov 2018 13:39:36 -0500 [thread overview] Message-ID: <20181128183936.GF20740@redhat.com> (raw) In-Reply-To: <CAHk-=wjgRO-=NPaU9EmrdC3it3o7kvf4u7sewv3crtNLkE13Hg@mail.gmail.com> On Wed, Nov 28, 2018 at 08:48:46AM -0800, Linus Torvalds wrote: > On Tue, Nov 27, 2018 at 7:20 PM Huang, Ying <ying.huang@intel.com> wrote: > > > > From the above data, for the parent commit 3 processes exited within > > 14s, another 3 exited within 100s. For this commit, the first process > > exited at 203s. That is, this commit makes memory allocation more fair > > among processes, so that processes proceeded at more similar speed. But > > this raises system memory footprint too, so triggered much more swap, > > thus lower benchmark score. Ok so it was the previous more unfair behavior that increased overall performance. It was also unclear to me that this was a full swap storm test. > > In general, memory allocation fairness among processes should be a good > > thing. So I think the report should have been a "performance > > improvement" instead of "performance regression". > > Hey, when you put it that way... > > Let's ignore this issue for now, and see if it shows up in some real > workload and people complain. Agreed. With regard to the other question about 4.4 backports, 4.0 didn't have __GFP_THISNODE, so this will still revert to the previous behavior and it won't risk to land into uncharted territory. So there should be no major concern for the backports. We should still work on improving this area, for now the idea was to apply a strict hotfix that would just revert to the previous behavior without introducing new features and new APIs, that would also have the side effect of diminishing THP utilization under MADV_HUGEPAGE. Thanks! Andrea
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com> To: lkp@lists.01.org Subject: Re: [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression Date: Wed, 28 Nov 2018 13:39:36 -0500 [thread overview] Message-ID: <20181128183936.GF20740@redhat.com> (raw) In-Reply-To: <CAHk-=wjgRO-=NPaU9EmrdC3it3o7kvf4u7sewv3crtNLkE13Hg@mail.gmail.com> [-- Attachment #1: Type: text/plain, Size: 1624 bytes --] On Wed, Nov 28, 2018 at 08:48:46AM -0800, Linus Torvalds wrote: > On Tue, Nov 27, 2018 at 7:20 PM Huang, Ying <ying.huang@intel.com> wrote: > > > > From the above data, for the parent commit 3 processes exited within > > 14s, another 3 exited within 100s. For this commit, the first process > > exited at 203s. That is, this commit makes memory allocation more fair > > among processes, so that processes proceeded at more similar speed. But > > this raises system memory footprint too, so triggered much more swap, > > thus lower benchmark score. Ok so it was the previous more unfair behavior that increased overall performance. It was also unclear to me that this was a full swap storm test. > > In general, memory allocation fairness among processes should be a good > > thing. So I think the report should have been a "performance > > improvement" instead of "performance regression". > > Hey, when you put it that way... > > Let's ignore this issue for now, and see if it shows up in some real > workload and people complain. Agreed. With regard to the other question about 4.4 backports, 4.0 didn't have __GFP_THISNODE, so this will still revert to the previous behavior and it won't risk to land into uncharted territory. So there should be no major concern for the backports. We should still work on improving this area, for now the idea was to apply a strict hotfix that would just revert to the previous behavior without introducing new features and new APIs, that would also have the side effect of diminishing THP utilization under MADV_HUGEPAGE. Thanks! Andrea
next prev parent reply other threads:[~2018-11-28 18:39 UTC|newest] Thread overview: 154+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-27 6:25 [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression kernel test robot 2018-11-27 6:25 ` kernel test robot 2018-11-27 17:08 ` [LKP] " Linus Torvalds 2018-11-27 17:08 ` Linus Torvalds 2018-11-27 18:17 ` [LKP] " Michal Hocko 2018-11-27 18:17 ` Michal Hocko 2018-11-27 18:21 ` [LKP] " Michal Hocko 2018-11-27 18:21 ` Michal Hocko 2018-11-27 19:05 ` [LKP] " Vlastimil Babka 2018-11-27 19:05 ` Vlastimil Babka 2018-11-27 19:16 ` [LKP] " Vlastimil Babka 2018-11-27 19:16 ` Vlastimil Babka 2018-11-27 20:57 ` [LKP] " Andrea Arcangeli 2018-11-27 20:57 ` Andrea Arcangeli 2018-11-27 22:50 ` [LKP] " Linus Torvalds 2018-11-27 22:50 ` Linus Torvalds 2018-11-28 6:30 ` [LKP] " Michal Hocko 2018-11-28 6:30 ` Michal Hocko 2018-11-28 3:20 ` [LKP] " Huang, Ying 2018-11-28 3:20 ` Huang, Ying 2018-11-28 16:48 ` [LKP] " Linus Torvalds 2018-11-28 16:48 ` Linus Torvalds 2018-11-28 18:39 ` Andrea Arcangeli [this message] 2018-11-28 18:39 ` Andrea Arcangeli 2018-11-28 23:10 ` [LKP] " David Rientjes 2018-11-28 23:10 ` David Rientjes 2018-12-03 18:01 ` [LKP] " Linus Torvalds 2018-12-03 18:01 ` Linus Torvalds 2018-12-03 18:14 ` [LKP] " Michal Hocko 2018-12-03 18:14 ` Michal Hocko 2018-12-03 18:19 ` [LKP] " Linus Torvalds 2018-12-03 18:19 ` Linus Torvalds 2018-12-03 18:30 ` [LKP] " Michal Hocko 2018-12-03 18:30 ` Michal Hocko 2018-12-03 18:45 ` [LKP] " Linus Torvalds 2018-12-03 18:45 ` Linus Torvalds 2018-12-03 18:59 ` [LKP] " Michal Hocko 2018-12-03 18:59 ` Michal Hocko 2018-12-03 19:23 ` [LKP] " Andrea Arcangeli 2018-12-03 19:23 ` Andrea Arcangeli 2018-12-03 20:26 ` [LKP] " David Rientjes 2018-12-03 20:26 ` David Rientjes 2018-12-03 19:28 ` [LKP] " Linus Torvalds 2018-12-03 19:28 ` Linus Torvalds 2018-12-03 20:12 ` [LKP] " Andrea Arcangeli 2018-12-03 20:12 ` Andrea Arcangeli 2018-12-03 20:36 ` [LKP] " David Rientjes 2018-12-03 20:36 ` David Rientjes 2018-12-03 22:04 ` [LKP] " Linus Torvalds 2018-12-03 22:04 ` Linus Torvalds 2018-12-03 22:27 ` [LKP] " Linus Torvalds 2018-12-03 22:27 ` Linus Torvalds 2018-12-03 22:57 ` [LKP] " David Rientjes 2018-12-03 22:57 ` David Rientjes 2018-12-04 9:22 ` [LKP] " Vlastimil Babka 2018-12-04 9:22 ` Vlastimil Babka 2018-12-04 10:45 ` [LKP] " Mel Gorman 2018-12-04 10:45 ` Mel Gorman 2018-12-05 0:47 ` [LKP] " David Rientjes 2018-12-05 0:47 ` David Rientjes 2018-12-05 9:08 ` [LKP] " Michal Hocko 2018-12-05 9:08 ` Michal Hocko 2018-12-05 10:43 ` [LKP] " Mel Gorman 2018-12-05 10:43 ` Mel Gorman 2018-12-05 11:43 ` [LKP] " Michal Hocko 2018-12-05 11:43 ` Michal Hocko 2018-12-05 10:06 ` [LKP] " Mel Gorman 2018-12-05 10:06 ` Mel Gorman 2018-12-05 20:40 ` [LKP] " Andrea Arcangeli 2018-12-05 20:40 ` Andrea Arcangeli 2018-12-05 21:59 ` [LKP] " David Rientjes 2018-12-05 21:59 ` David Rientjes 2018-12-06 0:00 ` [LKP] " Andrea Arcangeli 2018-12-06 0:00 ` Andrea Arcangeli 2018-12-05 22:03 ` [LKP] " Linus Torvalds 2018-12-05 22:03 ` Linus Torvalds 2018-12-05 22:12 ` [LKP] " David Rientjes 2018-12-05 22:12 ` David Rientjes 2018-12-05 23:36 ` [LKP] " Andrea Arcangeli 2018-12-05 23:36 ` Andrea Arcangeli 2018-12-05 23:51 ` [LKP] " Linus Torvalds 2018-12-05 23:51 ` Linus Torvalds 2018-12-06 0:58 ` [LKP] " Linus Torvalds 2018-12-06 0:58 ` Linus Torvalds 2018-12-06 9:14 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression) Michal Hocko 2018-12-06 9:14 ` MADV_HUGEPAGE vs. NUMA semantic (was: " Michal Hocko 2018-12-06 23:49 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] " David Rientjes 2018-12-06 23:49 ` MADV_HUGEPAGE vs. NUMA semantic (was: " David Rientjes 2018-12-07 7:34 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] " Michal Hocko 2018-12-07 7:34 ` MADV_HUGEPAGE vs. NUMA semantic (was: " Michal Hocko 2018-12-07 4:31 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] " Linus Torvalds 2018-12-07 4:31 ` MADV_HUGEPAGE vs. NUMA semantic (was: " Linus Torvalds 2018-12-07 7:49 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] " Michal Hocko 2018-12-07 7:49 ` MADV_HUGEPAGE vs. NUMA semantic (was: " Michal Hocko 2018-12-07 9:06 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] " Vlastimil Babka 2018-12-07 9:06 ` MADV_HUGEPAGE vs. NUMA semantic (was: " Vlastimil Babka 2018-12-07 23:15 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] " David Rientjes 2018-12-07 23:15 ` MADV_HUGEPAGE vs. NUMA semantic (was: " David Rientjes 2018-12-06 23:43 ` [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression David Rientjes 2018-12-06 23:43 ` David Rientjes 2018-12-07 4:01 ` [LKP] " Linus Torvalds 2018-12-07 4:01 ` Linus Torvalds 2018-12-10 0:29 ` [LKP] " David Rientjes 2018-12-10 0:29 ` David Rientjes 2018-12-10 4:49 ` [LKP] " Andrea Arcangeli 2018-12-10 4:49 ` Andrea Arcangeli 2018-12-12 0:37 ` [LKP] " David Rientjes 2018-12-12 0:37 ` David Rientjes 2018-12-12 9:50 ` [LKP] " Michal Hocko 2018-12-12 9:50 ` Michal Hocko 2018-12-12 17:00 ` [LKP] " Andrea Arcangeli 2018-12-12 17:00 ` Andrea Arcangeli 2018-12-14 11:32 ` [LKP] " Michal Hocko 2018-12-14 11:32 ` Michal Hocko 2018-12-12 10:14 ` [LKP] " Vlastimil Babka 2018-12-12 10:14 ` Vlastimil Babka 2018-12-14 21:04 ` [LKP] " David Rientjes 2018-12-14 21:04 ` David Rientjes 2018-12-14 21:33 ` [LKP] " Vlastimil Babka 2018-12-14 21:33 ` Vlastimil Babka 2018-12-21 22:18 ` [LKP] " David Rientjes 2018-12-21 22:18 ` David Rientjes 2018-12-21 22:18 ` [LKP] " David Rientjes 2018-12-22 12:08 ` Mel Gorman 2018-12-22 12:08 ` Mel Gorman 2018-12-14 23:11 ` [LKP] " Mel Gorman 2018-12-14 23:11 ` Mel Gorman 2018-12-21 22:15 ` [LKP] " David Rientjes 2018-12-21 22:15 ` David Rientjes 2018-12-12 10:44 ` [LKP] " Andrea Arcangeli 2018-12-12 10:44 ` Andrea Arcangeli 2019-04-15 11:48 ` [LKP] " Michal Hocko 2019-04-15 11:48 ` Michal Hocko 2018-12-06 0:18 ` [LKP] " David Rientjes 2018-12-06 0:18 ` David Rientjes 2018-12-06 0:54 ` [LKP] " Andrea Arcangeli 2018-12-06 0:54 ` Andrea Arcangeli 2018-12-06 9:23 ` [LKP] " Vlastimil Babka 2018-12-06 9:23 ` Vlastimil Babka 2018-12-03 20:39 ` [LKP] " David Rientjes 2018-12-03 20:39 ` David Rientjes 2018-12-03 21:25 ` [LKP] " Michal Hocko 2018-12-03 21:25 ` Michal Hocko 2018-12-03 21:53 ` [LKP] " David Rientjes 2018-12-03 21:53 ` David Rientjes 2018-12-04 8:48 ` [LKP] " Michal Hocko 2018-12-04 8:48 ` Michal Hocko 2018-12-05 0:07 ` [LKP] " David Rientjes 2018-12-05 0:07 ` David Rientjes 2018-12-05 10:18 ` [LKP] " Michal Hocko 2018-12-05 10:18 ` Michal Hocko 2018-12-05 19:16 ` [LKP] " David Rientjes 2018-12-05 19:16 ` David Rientjes 2018-11-27 7:23 [LKP] " kernel test robot
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