From: Pasha Tatashin <pasha.tatashin@oracle.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, borntraeger@de.ibm.com,
heiko.carstens@de.ibm.com, davem@davemloft.net
Subject: Re: [v3 0/9] parallelized "struct page" zeroing
Date: Thu, 11 May 2017 16:47:05 -0400 [thread overview]
Message-ID: <9088ad7e-8b3b-8eba-2fdf-7b0e36e4582e@oracle.com> (raw)
In-Reply-To: <ab667486-54a0-a36e-6797-b5f7b83c10f7@oracle.com>
>>
>> Have you measured that? I do not think it would be super hard to
>> measure. I would be quite surprised if this added much if anything at
>> all as the whole struct page should be in the cache line already. We do
>> set reference count and other struct members. Almost nobody should be
>> looking at our page at this time and stealing the cache line. On the
>> other hand a large memcpy will basically wipe everything away from the
>> cpu cache. Or am I missing something?
>>
Here is data for single thread (deferred struct page init is disabled):
Intel CPU E7-8895 v3 @ 2.60GHz 1T memory
-----------------------------------------
time to memset "struct pages in memblock: 11.28s
time to init "struct pag"es: 4.90s
Moving memset into __init_single_page()
time to init and memset "struct page"es: 8.39s
SPARC M6 @ 3600 MHz 1T memory
-----------------------------------------
time to memset "struct pages in memblock: 1.60s
time to init "struct pag"es: 3.37s
Moving memset into __init_single_page()
time to init and memset "struct page"es: 12.99s
So, moving memset() into __init_single_page() benefits Intel. I am
actually surprised why memset() is so slow on intel when it is called
from memblock. But, hurts SPARC, I guess these membars at the end of
memset() kills the performance.
Also, when looking at these values, remeber that Intel has twice as many
"struct page" for the same amount of memory.
Pasha
next prev parent reply other threads:[~2017-05-11 20:47 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-05 17:03 [v3 0/9] parallelized "struct page" zeroing Pavel Tatashin
2017-05-05 17:03 ` [v3 1/9] sparc64: simplify vmemmap_populate Pavel Tatashin
2017-05-05 17:03 ` [v3 2/9] mm: defining memblock_virt_alloc_try_nid_raw Pavel Tatashin
2017-05-05 17:03 ` [v3 3/9] mm: add "zero" argument to vmemmap allocators Pavel Tatashin
2017-05-13 19:17 ` kbuild test robot
2017-05-05 17:03 ` [v3 4/9] mm: do not zero vmemmap_buf Pavel Tatashin
2017-05-05 17:03 ` [v3 5/9] mm: zero struct pages during initialization Pavel Tatashin
2017-05-05 17:03 ` [v3 6/9] sparc64: teach sparc not to zero struct pages memory Pavel Tatashin
2017-05-05 17:03 ` [v3 7/9] x86: teach x86 " Pavel Tatashin
2017-05-05 17:03 ` [v3 8/9] powerpc: teach platforms " Pavel Tatashin
2017-05-05 17:03 ` [v3 9/9] s390: " Pavel Tatashin
2017-05-08 11:36 ` Heiko Carstens
2017-05-15 18:24 ` Pasha Tatashin
2017-05-15 23:17 ` Heiko Carstens
2017-05-16 0:33 ` Pasha Tatashin
2017-05-09 18:12 ` [v3 0/9] parallelized "struct page" zeroing Michal Hocko
2017-05-09 18:54 ` Pasha Tatashin
2017-05-10 7:24 ` Michal Hocko
2017-05-10 13:42 ` Pasha Tatashin
2017-05-10 14:57 ` Michal Hocko
2017-05-10 15:01 ` Pasha Tatashin
2017-05-10 15:20 ` David Miller
2017-05-11 20:47 ` Pasha Tatashin [this message]
2017-05-11 20:59 ` Pasha Tatashin
2017-05-12 16:57 ` David Miller
2017-05-12 17:24 ` Pasha Tatashin
2017-05-12 17:37 ` David Miller
2017-05-16 23:50 ` Benjamin Herrenschmidt
2017-05-12 16:56 ` David Miller
2017-05-10 15:19 ` David Miller
2017-05-10 17:17 ` Matthew Wilcox
2017-05-10 18:00 ` David Miller
2017-05-10 21:11 ` Matthew Wilcox
2017-05-11 8:05 ` Michal Hocko
2017-05-11 14:35 ` David Miller
2017-05-15 18:12 ` Pasha Tatashin
2017-05-15 19:38 ` Michal Hocko
2017-05-15 20:44 ` Pasha Tatashin
2017-05-16 8:36 ` Michal Hocko
2017-05-26 16:45 ` Pasha Tatashin
2017-05-29 11:53 ` Michal Hocko
2017-05-30 17:16 ` Pasha Tatashin
2017-05-31 16:31 ` Michal Hocko
2017-05-31 16:51 ` David Miller
2017-06-01 3:35 ` Pasha Tatashin
2017-06-01 8:46 ` Michal Hocko
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