From: Daniel Jordan <daniel.m.jordan@oracle.com>
To: Aaron Lu <aaron.lu@intel.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Huang Ying <ying.huang@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Kemi Wang <kemi.wang@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>, Michal Hocko <mhocko@suse.com>,
Mel Gorman <mgorman@techsingularity.net>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [RFC PATCH v2 0/4] Eliminate zone->lock contention for will-it-scale/page_fault1 and parallel free
Date: Thu, 22 Mar 2018 07:20:14 -0400 [thread overview]
Message-ID: <5fa1b7f6-4614-c0d9-9f85-007cdd049a5b@oracle.com> (raw)
In-Reply-To: <20180322013049.GA4056@intel.com>
On 03/21/2018 09:30 PM, Aaron Lu wrote:
> On Wed, Mar 21, 2018 at 01:44:25PM -0400, Daniel Jordan wrote:
>> On 03/20/2018 04:54 AM, Aaron Lu wrote:
>> ...snip...
>>> reduced zone->lock contention on free path from 35% to 1.1%. Also, it
>>> shows good result on parallel free(*) workload by reducing zone->lock
>>> contention from 90% to almost zero(lru lock increased from almost 0 to
>>> 90% though).
>>
>> Hi Aaron, I'm looking through your series now. Just wanted to mention that I'm seeing the same interaction between zone->lock and lru_lock in my own testing. IOW, it's not enough to fix just one or the other: both need attention to get good performance on a big system, at least in this microbenchmark we've both been using.
>
> Agree.
>
>>
>> There's anti-scaling at high core counts where overall system page faults per second actually decrease with more CPUs added to the test. This happens when either zone->lock or lru_lock contention are completely removed, but the anti-scaling goes away when both locks are fixed.
>>
>> Anyway, I'll post some actual data on this stuff soon.
>
> Looking forward to that, thanks.
>
> In the meantime, I'll also try your lru_lock optimization work on top of
> this patchset to see if the lock contention shifts back to zone->lock.
The lru_lock series I posted is pretty outdated by now, and I've got a
totally new approach I plan to post soon, so it might make sense to wait
for that.
next prev parent reply other threads:[~2018-03-22 11:21 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-20 8:54 [RFC PATCH v2 0/4] Eliminate zone->lock contention for will-it-scale/page_fault1 and parallel free Aaron Lu
2018-03-20 8:54 ` [RFC PATCH v2 1/4] mm/page_alloc: use helper functions to add/remove a page to/from buddy Aaron Lu
2018-03-20 11:35 ` Vlastimil Babka
2018-03-20 13:50 ` Aaron Lu
2018-03-20 8:54 ` [RFC PATCH v2 2/4] mm/__free_one_page: skip merge for order-0 page unless compaction failed Aaron Lu
2018-03-20 11:45 ` Vlastimil Babka
2018-03-20 14:11 ` Aaron Lu
2018-03-21 7:53 ` Vlastimil Babka
2018-03-22 17:15 ` Matthew Wilcox
2018-03-22 18:39 ` Daniel Jordan
2018-03-22 18:50 ` Matthew Wilcox
2018-03-20 22:58 ` Figo.zhang
2018-03-21 1:59 ` Aaron Lu
2018-03-21 4:21 ` Figo.zhang
2018-03-21 4:53 ` Aaron Lu
2018-03-21 5:59 ` Figo.zhang
2018-03-21 7:42 ` Aaron Lu
2018-03-20 8:54 ` [RFC PATCH v2 3/4] mm/rmqueue_bulk: alloc without touching individual page structure Aaron Lu
2018-03-20 22:29 ` Figo.zhang
2018-03-21 1:52 ` Aaron Lu
2018-03-21 12:55 ` Vlastimil Babka
2018-03-21 15:01 ` Aaron Lu
2018-03-29 19:16 ` Daniel Jordan
2018-03-20 8:54 ` [RFC PATCH v2 4/4] mm/free_pcppages_bulk: reduce overhead of cluster operation on free path Aaron Lu
2018-03-21 17:44 ` [RFC PATCH v2 0/4] Eliminate zone->lock contention for will-it-scale/page_fault1 and parallel free Daniel Jordan
2018-03-22 1:30 ` Aaron Lu
2018-03-22 11:20 ` Daniel Jordan [this message]
2018-03-29 19:19 ` Daniel Jordan
2018-03-30 1:42 ` Aaron Lu
2018-03-30 14:27 ` Daniel Jordan
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