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From: Vlastimil Babka <vbabka@suse.cz>
To: Mike Galbraith <efault@gmx.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Christoph Lameter <cl@linux.com>,
	David Rientjes <rientjes@google.com>,
	Pekka Enberg <penberg@kernel.org>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Mel Gorman <mgorman@techsingularity.net>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Jann Horn <jannh@google.com>
Subject: Re: [RFC v2 00/34] SLUB: reduce irq disabled scope and make it RT compatible
Date: Sun, 18 Jul 2021 09:41:49 +0200	[thread overview]
Message-ID: <ef4903e2-c2ce-9a64-68b0-c7ee483eb582@suse.cz> (raw)
In-Reply-To: <891dc24e38106f8542f4c72831d52dc1a1863ae8.camel@gmx.de>

On 7/3/21 9:24 AM, Mike Galbraith wrote:
> On Fri, 2021-07-02 at 20:29 +0200, Sebastian Andrzej Siewior wrote:
>> I replaced my slub changes with slub-local-lock-v2r3.
>> I haven't seen any complains from lockdep or so which is good. Then I
>> did this with RT enabled (and no debug):
> 
> Below is some raw hackbench data from my little i4790 desktop box.  It
> says we'll definitely still want list_lock to be raw.

Hi Mike, thanks a lot for the testing, sorry for late reply.

Did you try, instead of raw list_lock, not applying the last, local lock
patch, as I suggested in reply to bigeasy? I think the impact at
reducing the RT-specific overhead would be larger (than raw list_lock),
the result should still be RT compatible, and it would also deal with
the bugs you found there... (which I'll look into).

Thanks,
Vlastimil

> It also appears to be saying that there's something RT specific to
> stare at in addition to the list_lock business, but add a pinch of salt
> to that due to the config of the virgin(ish) tip tree being much
> lighter than the enterprise(ish) config of the tip-rt tree.
> 
> perf stat -r10 hackbench -s4096 -l500
> full warmup, record, repeat twice for elapsed
> 
> 5.13.0.g60ab3ed-tip-rt
>           8,898.51 msec task-clock                #    7.525 CPUs utilized            ( +-  0.33% )
>            368,922      context-switches          #    0.041 M/sec                    ( +-  5.20% )
>             42,281      cpu-migrations            #    0.005 M/sec                    ( +-  5.28% )
>             13,180      page-faults               #    0.001 M/sec                    ( +-  0.70% )
>     33,343,378,867      cycles                    #    3.747 GHz                      ( +-  0.30% )
>     21,656,783,887      instructions              #    0.65  insn per cycle           ( +-  0.67% )
>      4,408,569,663      branches                  #  495.428 M/sec                    ( +-  0.73% )
>         12,040,125      branch-misses             #    0.27% of all branches          ( +-  2.93% )
> 
>            1.18260 +- 0.00473 seconds time elapsed  ( +-  0.40% )
>            1.19018 +- 0.00441 seconds time elapsed  ( +-  0.37% ) (repeat)
>            1.18260 +- 0.00473 seconds time elapsed  ( +-  0.40% ) (repeat)
> 
> 5.13.0.g60ab3ed-tip-rt +slub-local-lock-v2r3 list_lock=raw_spinlock_t
>           9,642.00 msec task-clock                #    7.521 CPUs utilized            ( +-  0.46% )
>            462,091      context-switches          #    0.048 M/sec                    ( +-  4.79% )
>             44,411      cpu-migrations            #    0.005 M/sec                    ( +-  4.34% )
>             12,980      page-faults               #    0.001 M/sec                    ( +-  0.43% )
>     36,098,859,429      cycles                    #    3.744 GHz                      ( +-  0.44% )
>     25,462,853,462      instructions              #    0.71  insn per cycle           ( +-  0.50% )
>      5,260,898,360      branches                  #  545.623 M/sec                    ( +-  0.52% )
>         16,088,686      branch-misses             #    0.31% of all branches          ( +-  2.02% )
> 
>            1.28207 +- 0.00568 seconds time elapsed  ( +-  0.44% )
>            1.28744 +- 0.00713 seconds time elapsed  ( +-  0.55% ) (repeat)
>            1.28085 +- 0.00850 seconds time elapsed  ( +-  0.66% ) (repeat)
> 
> 5.13.0.g60ab3ed-tip-rt +slub-local-lock-v2r3 list_lock=spinlock_t
>          10,004.89 msec task-clock                #    6.029 CPUs utilized            ( +-  1.37% )
>            654,311      context-switches          #    0.065 M/sec                    ( +-  5.16% )
>            211,070      cpu-migrations            #    0.021 M/sec                    ( +-  1.38% )
>             13,262      page-faults               #    0.001 M/sec                    ( +-  0.79% )
>     36,585,914,931      cycles                    #    3.657 GHz                      ( +-  1.35% )
>     27,682,240,511      instructions              #    0.76  insn per cycle           ( +-  1.06% )
>      5,766,064,432      branches                  #  576.325 M/sec                    ( +-  1.11% )
>         24,269,069      branch-misses             #    0.42% of all branches          ( +-  2.03% )
> 
>             1.6595 +- 0.0116 seconds time elapsed  ( +-  0.70% )
>             1.6270 +- 0.0180 seconds time elapsed  ( +-  1.11% ) (repeat)
>             1.6213 +- 0.0150 seconds time elapsed  ( +-  0.93% ) (repeat)
> 
> virgin(ish) tip
> 5.13.0.g60ab3ed-tip
>           7,320.67 msec task-clock                #    7.792 CPUs utilized            ( +-  0.31% )
>            221,215      context-switches          #    0.030 M/sec                    ( +-  3.97% )
>             16,234      cpu-migrations            #    0.002 M/sec                    ( +-  4.07% )
>             13,233      page-faults               #    0.002 M/sec                    ( +-  0.91% )
>     27,592,205,252      cycles                    #    3.769 GHz                      ( +-  0.32% )
>      8,309,495,040      instructions              #    0.30  insn per cycle           ( +-  0.37% )
>      1,555,210,607      branches                  #  212.441 M/sec                    ( +-  0.42% )
>          5,484,209      branch-misses             #    0.35% of all branches          ( +-  2.13% )
> 
>            0.93949 +- 0.00423 seconds time elapsed  ( +-  0.45% )
>            0.94608 +- 0.00384 seconds time elapsed  ( +-  0.41% ) (repeat)
>            0.94422 +- 0.00410 seconds time elapsed  ( +-  0.43% )
> 
> 5.13.0.g60ab3ed-tip +slub-local-lock-v2r3
>           7,343.57 msec task-clock                #    7.776 CPUs utilized            ( +-  0.44% )
>            223,044      context-switches          #    0.030 M/sec                    ( +-  3.02% )
>             16,057      cpu-migrations            #    0.002 M/sec                    ( +-  4.03% )
>             13,164      page-faults               #    0.002 M/sec                    ( +-  0.97% )
>     27,684,906,017      cycles                    #    3.770 GHz                      ( +-  0.45% )
>      8,323,273,871      instructions              #    0.30  insn per cycle           ( +-  0.28% )
>      1,556,106,680      branches                  #  211.901 M/sec                    ( +-  0.31% )
>          5,463,468      branch-misses             #    0.35% of all branches          ( +-  1.33% )
> 
>            0.94440 +- 0.00352 seconds time elapsed  ( +-  0.37% )
>            0.94830 +- 0.00228 seconds time elapsed  ( +-  0.24% ) (repeat)
>            0.93813 +- 0.00440 seconds time elapsed  ( +-  0.47% ) (repeat)
> 


  parent reply	other threads:[~2021-07-18  7:42 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-09 11:38 Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 01/34] mm, slub: don't call flush_all() from list_locations() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 02/34] mm, slub: allocate private object map for sysfs listings Vlastimil Babka
2021-06-09 13:29   ` Christoph Lameter
2021-06-09 13:29     ` Christoph Lameter
2021-06-09 11:38 ` [RFC v2 03/34] mm, slub: allocate private object map for validate_slab_cache() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 04/34] mm, slub: don't disable irq for debug_check_no_locks_freed() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 05/34] mm, slub: remove redundant unfreeze_partials() from put_cpu_partial() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 06/34] mm, slub: unify cmpxchg_double_slab() and __cmpxchg_double_slab() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 07/34] mm, slub: extract get_partial() from new_slab_objects() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 08/34] mm, slub: dissolve new_slab_objects() into ___slab_alloc() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 09/34] mm, slub: return slab page from get_partial() and set c->page afterwards Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 10/34] mm, slub: restructure new page checks in ___slab_alloc() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 11/34] mm, slub: simplify kmem_cache_cpu and tid setup Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 12/34] mm, slub: move disabling/enabling irqs to ___slab_alloc() Vlastimil Babka
2021-07-06  4:38   ` Mike Galbraith
2021-07-06  4:38     ` Mike Galbraith
2021-06-09 11:38 ` [RFC v2 13/34] mm, slub: do initial checks in ___slab_alloc() with irqs enabled Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 14/34] mm, slub: move disabling irqs closer to get_partial() in ___slab_alloc() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 15/34] mm, slub: restore irqs around calling new_slab() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 16/34] mm, slub: validate slab from partial list or page allocator before making it cpu slab Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 17/34] mm, slub: check new pages with restored irqs Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 18/34] mm, slub: stop disabling irqs around get_partial() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 19/34] mm, slub: move reset of c->page and freelist out of deactivate_slab() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 20/34] mm, slub: make locking in deactivate_slab() irq-safe Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 21/34] mm, slub: call deactivate_slab() without disabling irqs Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 22/34] mm, slub: move irq control into unfreeze_partials() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 23/34] mm, slub: discard slabs in unfreeze_partials() without irqs disabled Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 24/34] mm, slub: detach whole partial list at once in unfreeze_partials() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 25/34] mm, slub: detach percpu partial list in unfreeze_partials() using this_cpu_cmpxchg() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 26/34] mm, slub: only disable irq with spin_lock in __unfreeze_partials() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 27/34] mm, slub: don't disable irqs in slub_cpu_dead() Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 28/34] mm, slab: make flush_slab() possible to call with irqs enabled Vlastimil Babka
2021-06-09 11:38 ` [RFC v2 29/34] mm: slub: Move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context Vlastimil Babka
2021-06-09 22:29   ` Cyrill Gorcunov
2021-06-10  8:32     ` Vlastimil Babka
2021-06-10  8:36       ` Cyrill Gorcunov
2021-07-07  6:33   ` Hillf Danton
2021-06-09 11:38 ` [RFC v2 30/34] mm: slub: Make object_map_lock a raw_spinlock_t Vlastimil Babka
2021-06-09 11:39 ` [RFC v2 31/34] mm, slub: optionally save/restore irqs in slab_[un]lock()/ Vlastimil Babka
2021-07-02 12:17   ` Sebastian Andrzej Siewior
2021-06-09 11:39 ` [RFC v2 32/34] mm, slub: make slab_lock() disable irqs with PREEMPT_RT Vlastimil Babka
2021-06-09 11:39 ` [RFC v2 33/34] mm, slub: use migrate_disable() on PREEMPT_RT Vlastimil Babka
2021-06-14 11:07   ` Vlastimil Babka
2021-06-14 11:16     ` Sebastian Andrzej Siewior
2021-06-14 11:33       ` Vlastimil Babka
2021-06-14 12:54         ` Vlastimil Babka
2021-06-14 14:01         ` Sebastian Andrzej Siewior
2021-06-09 11:39 ` [RFC v2 34/34] mm, slub: convert kmem_cpu_slab protection to local_lock Vlastimil Babka
2021-06-14  9:49 ` [RFC v2 00/34] SLUB: reduce irq disabled scope and make it RT compatible Mel Gorman
2021-06-14 11:31   ` Mel Gorman
2021-06-14 11:10 ` Vlastimil Babka
2021-07-02 18:29 ` Sebastian Andrzej Siewior
2021-07-02 20:25   ` Vlastimil Babka
2021-07-29 13:49     ` Sebastian Andrzej Siewior
2021-07-29 14:17       ` Vlastimil Babka
2021-07-29 14:37         ` Sebastian Andrzej Siewior
2021-07-03  7:24   ` Mike Galbraith
2021-07-03 15:47     ` Mike Galbraith
2021-07-04  5:37       ` Mike Galbraith
2021-07-18  7:41     ` Vlastimil Babka [this message]
2021-07-18  8:29       ` Mike Galbraith
2021-07-18 12:09         ` Mike Galbraith
2021-07-05 16:00   ` Mike Galbraith
2021-07-06 17:56     ` Mike Galbraith

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