From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Vlastimil Babka <vbabka@suse.cz>
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: Fri, 2 Jul 2021 20:29:44 +0200 [thread overview]
Message-ID: <20210702182944.lqa7o2a25to6czju@linutronix.de> (raw)
In-Reply-To: <20210609113903.1421-1-vbabka@suse.cz>
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):
- A "time make -j32" run of allmodconfig on /dev/shm.
Old:
| real 20m6,217s
| user 568m22,553s
| sys 48m33,126s
New:
| real 20m9,049s
| user 569m32,096s
| sys 48m47,670s
These 3 seconds here are probably in the noise range.
- perf_5.10 stat -r 10 hackbench -g200 -s 4096 -l500
Old:
| 464.967,20 msec task-clock # 27,220 CPUs utilized ( +- 0,16% )
| 7.683.944 context-switches # 0,017 M/sec ( +- 0,86% )
| 931.380 cpu-migrations # 0,002 M/sec ( +- 4,94% )
| 219.569 page-faults # 0,472 K/sec ( +- 0,39% )
| 1.104.727.599.918 cycles # 2,376 GHz ( +- 0,18% )
| 941.428.898.087 stalled-cycles-frontend # 85,22% frontend cycles idle ( +- 0,24% )
| 729.016.546.572 stalled-cycles-backend # 65,99% backend cycles idle ( +- 0,32% )
| 340.133.571.519 instructions # 0,31 insn per cycle
| # 2,77 stalled cycles per insn ( +- 0,12% )
| 73.746.821.314 branches # 158,607 M/sec ( +- 0,13% )
| 377.838.006 branch-misses # 0,51% of all branches ( +- 1,01% )
|
| 17,0820 +- 0,0202 seconds time elapsed ( +- 0,12% )
New:
| 422.865,71 msec task-clock # 4,782 CPUs utilized ( +- 0,34% )
| 14.594.238 context-switches # 0,035 M/sec ( +- 0,43% )
| 3.737.926 cpu-migrations # 0,009 M/sec ( +- 0,46% )
| 218.474 page-faults # 0,517 K/sec ( +- 0,74% )
| 940.715.812.020 cycles # 2,225 GHz ( +- 0,34% )
| 716.593.827.820 stalled-cycles-frontend # 76,18% frontend cycles idle ( +- 0,39% )
| 550.730.862.839 stalled-cycles-backend # 58,54% backend cycles idle ( +- 0,43% )
| 417.274.588.907 instructions # 0,44 insn per cycle
| # 1,72 stalled cycles per insn ( +- 0,17% )
| 92.814.150.290 branches # 219,488 M/sec ( +- 0,17% )
| 822.102.170 branch-misses # 0,89% of all branches ( +- 0,41% )
|
| 88,427 +- 0,618 seconds time elapsed ( +- 0,70% )
So this is outside of the noise range.
I'm not sure where this is coming from. My guess would be higher lock
contention within the memory allocator.
> The remaining patches to upstream from the RT tree are small ones related to
> KConfig. The patch that restricts PREEMPT_RT to SLUB (not SLAB or SLOB) makes
> sense. The patch that disables CONFIG_SLUB_CPU_PARTIAL with PREEMPT_RT could
> perhaps be re-evaluated as the series also addresses some latency issues with
> percpu partial slabs.
With that series the PARTIAL slab can be indeed enabled. I have (had) a
half done series where I had PARTIAL enabled and noticed a slight
increase in latency so made it "default y on !RT". It wasn't dramatic
but appeared to be outside of noise.
Sebastian
next prev parent reply other threads:[~2021-07-02 18:29 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 11:38 [RFC v2 00/34] SLUB: reduce irq disabled scope and make it RT compatible 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210702182944.lqa7o2a25to6czju@linutronix.de \
--to=bigeasy@linutronix.de \
--cc=brouer@redhat.com \
--cc=cl@linux.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=jannh@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=penberg@kernel.org \
--cc=peterz@infradead.org \
--cc=rientjes@google.com \
--cc=tglx@linutronix.de \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.