From: Dave Hansen <dave.hansen@linux.intel.com>
To: Lukasz Anaczkowski <lukasz.anaczkowski@intel.com>,
hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de,
ak@linux.intel.com, kirill.shutemov@linux.intel.com,
mhocko@suse.com, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: harish.srinivasappa@intel.com, lukasz.odzioba@intel.com,
grzegorz.andrejczuk@intel.com, lukasz.daniluk@intel.com
Subject: Re: [PATCH v3] Linux VM workaround for Knights Landing A/D leak
Date: Thu, 16 Jun 2016 13:23:58 -0700 [thread overview]
Message-ID: <57630ADE.3040900@linux.intel.com> (raw)
In-Reply-To: <1466090042-30908-1-git-send-email-lukasz.anaczkowski@intel.com>
On 06/16/2016 08:14 AM, Lukasz Anaczkowski wrote:
> For reclaim this brings the performance back to before Mel's
> flushing changes, but for unmap it disables batching.
This turns out to be pretty catastrophic for unmap. In a workload that
uses, say 200 hardware threads and alloc/frees() a few MB/sec, this ends
up costing hundreds of thousands of extra received IPIs. 10MB=~2500
ptes, and at with 200 threads, that's 250,000 IPIs received just to free
10MB of memory.
The initial testing we did on this was on a *bunch* of threads all doing
alloc/free. But this is bottlenecked on other things, like mmap_sem
being held for write.
The scenario that we really needed to test here was on lots of threads
doing processing and 1 thread doing alloc/free.
next prev parent reply other threads:[~2016-06-16 20:24 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-14 15:58 [PATCH] Linux VM workaround for Knights Landing A/D leak Lukasz Anaczkowski
2016-06-14 16:31 ` kbuild test robot
2016-06-14 16:47 ` Nadav Amit
2016-06-14 16:54 ` Anaczkowski, Lukasz
2016-06-14 17:01 ` [PATCH v2] " Lukasz Anaczkowski
2016-06-14 17:24 ` Dave Hansen
2016-06-14 18:34 ` One Thousand Gnomes
2016-06-14 18:54 ` Dave Hansen
2016-06-14 19:19 ` Borislav Petkov
2016-06-14 20:20 ` H. Peter Anvin
2016-06-14 20:47 ` Borislav Petkov
2016-06-14 20:54 ` H. Peter Anvin
2016-06-14 21:02 ` Borislav Petkov
2016-06-14 21:08 ` H. Peter Anvin
2016-06-14 21:13 ` H. Peter Anvin
2016-06-14 18:10 ` Borislav Petkov
2016-06-15 13:12 ` Anaczkowski, Lukasz
2016-06-14 18:38 ` Nadav Amit
2016-06-15 13:12 ` Anaczkowski, Lukasz
2016-06-15 20:04 ` Nadav Amit
2016-06-15 20:10 ` Dave Hansen
2016-06-15 20:26 ` Nadav Amit
2016-06-16 15:14 ` [PATCH v3] " Lukasz Anaczkowski
2016-06-16 16:43 ` Nadav Amit
2016-06-16 20:23 ` Dave Hansen [this message]
2016-06-14 17:18 ` [PATCH] " Dave Hansen
2016-06-14 20:16 ` Nadav Amit
2016-06-14 21:37 ` Dave Hansen
2016-06-15 2:20 ` Andy Lutomirski
2016-06-15 2:35 ` Nadav Amit
2016-06-15 2:36 ` Andy Lutomirski
2016-06-15 2:44 ` Nadav Amit
2016-06-15 3:09 ` Andy Lutomirski
2016-06-15 3:20 ` Nadav Amit
2016-06-14 16:58 ` kbuild test robot
2016-06-14 17:19 ` Dave Hansen
2016-06-15 13:06 ` Anaczkowski, Lukasz
2016-06-14 17:47 ` kbuild test robot
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