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Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression

From Mel Gorman <mgorman@techsingularity.net>
Newsgroups linux.kernel
Subject Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression
Date 2016-08-20 14:20 +0200
Message-ID <s8dpL-2O3-7@gated-at.bofh.it> (permalink)
References (5 earlier) <s7HpU-7RC-27@gated-at.bofh.it> <s7HSW-892-21@gated-at.bofh.it> <s7HSW-892-19@gated-at.bofh.it> <s7PGN-4yC-9@gated-at.bofh.it> <s81HX-3Le-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Sat, Aug 20, 2016 at 09:48:39AM +1000, Dave Chinner wrote:
> On Fri, Aug 19, 2016 at 11:49:46AM +0100, Mel Gorman wrote:
> > On Thu, Aug 18, 2016 at 03:25:40PM -0700, Linus Torvalds wrote:
> > > It *could* be as simple/stupid as just saying "let's allocate the page
> > > cache for new pages from the current node" - and if the process that
> > > dirties pages just stays around on one single node, that might already
> > > be sufficient.
> > > 
> > > So just for testing purposes, you could try changing that
> > > 
> > >         return alloc_pages(gfp, 0);
> > > 
> > > in __page_cache_alloc() into something like
> > > 
> > >         return alloc_pages_node(cpu_to_node(raw_smp_processor_id())), gfp, 0);
> > > 
> > > or something.
> > > 
> > 
> > The test would be interesting but I believe that keeping heavy writers
> > on one node will force them to stall early on dirty balancing even if
> > there is plenty of free memory on other nodes.
> 
> Well, it depends on the speed of the storage. The higher the speed
> of the storage, the less we care about stalling on dirty pages
> during reclaim. i.e. faster storage == shorter stalls. We really
> should stop thinking we need to optimise reclaim purely for the
> benefit of slow disks.  500MB/s write speed with latencies of a
> under a couple of milliseconds is common hardware these days. pcie
> based storage (e.g. m2, nvme) is rapidly becoming commonplace and
> they can easily do 1-2GB/s write speeds.
> 

I partially agree. I've been of the opinion for a long time that dirty_time
would be desirable and limit the amount of dirty data by microseconds
required to sync the data and pick a default like 5 seconds. It's
non-trivial as the write speed of all BDIs would have to be estimated
and on rotary storage the estimate would be unreliable.

A short-term practical idea would be to distribute pages for writing
only when the dirty limit is almost reached on a given node. For fast
storage, the distribution may never happen.

Neither idea would actually impact the current problem though unless it
was combined with discarding clean cache agressively if the underlying
storage is fast. Hence, it would still be nice if the contention problem
could be mitigated. Did that last patch help any?

-- 
Mel Gorman
SUSE Labs

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Re: [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-11 01:10 +0200
  Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-11 02:00 +0200
    Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-11 02:20 +0200
      Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-11 02:30 +0200
        Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-11 02:40 +0200
          Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-11 03:10 +0200
            Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-11 06:50 +0200
              Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-15 19:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-16 02:30 +0200
            Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-11 18:00 +0200
              Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-11 19:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-11 20:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-11 22:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-11 22:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-11 22:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Al Viro <viro@ZenIV.linux.org.uk> - 2016-08-12 00:20 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-12 00:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-11 23:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-12 00:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-12 03:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-12 04:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-12 06:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-12 20:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-14 11:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-15 02:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-15 03:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-15 04:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-15 05:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-15 07:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-16 00:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-16 00:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 01:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 01:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-16 02:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Mel Gorman <mgorman@techsingularity.net> - 2016-08-16 17:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 20:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Michal Hocko <mhocko@kernel.org> - 2016-08-17 17:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Michal Hocko <mhocko@kernel.org> - 2016-08-17 18:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Mel Gorman <mgorman@techsingularity.net> - 2016-08-17 17:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Mel Gorman <mgorman@techsingularity.net> - 2016-08-18 02:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-18 09:20 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Mel Gorman <mgorman@techsingularity.net> - 2016-08-18 15:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-19 04:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-19 04:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Michal Hocko <mhocko@kernel.org> - 2016-08-19 11:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Mel Gorman <mgorman@techsingularity.net> - 2016-08-19 13:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-20 01:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-20 03:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Mel Gorman <mgorman@techsingularity.net> - 2016-08-20 14:20 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-19 06:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Mel Gorman <mgorman@techsingularity.net> - 2016-08-19 17:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-24 17:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-18 04:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 02:20 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-16 02:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 03:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-16 02:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 04:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-17 00:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-17 01:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 01:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-16 02:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-16 02:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Ingo Molnar <mingo@kernel.org> - 2016-08-15 07:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Peter Zijlstra <peterz@infradead.org> - 2016-08-17 18:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-15 15:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-12 04:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-12 04:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-12 05:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-12 05:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-12 06:20 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-12 07:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-12 08:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Ye Xiaolong <xiaolong.ye@intel.com> - 2016-08-12 08:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Ye Xiaolong <xiaolong.ye@intel.com> - 2016-08-12 11:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-12 12:10 +0200
                Re: [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-12 12:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-13 02:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-14 10:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-14 10:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-14 11:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-14 11:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%  regression Christoph Hellwig <hch@lst.de> - 2016-08-14 18:20 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-15 01:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-15 02:00 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-15 16:20 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-15 23:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-16 14:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-15 22:40 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6%     regression "Huang\, Ying" <ying.huang@intel.com> - 2016-08-23 00:10 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Fengguang Wu <fengguang.wu@intel.com> - 2016-08-16 15:30 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-14 12:00 +0200
          Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-11 03:20 +0200
            Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-11 03:40 +0200
              Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Ye Xiaolong <xiaolong.ye@intel.com> - 2016-08-11 04:50 +0200
                Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-11 05:20 +0200
            Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Dave Chinner <david@fromorbit.com> - 2016-08-12 03:30 +0200
  Re: [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-11 02:00 +0200

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