From: "liupeng (DM)" <liupeng256@huawei.com>
To: "david@redhat.com" <david@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"vbabka@suse.cz" <vbabka@suse.cz>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: [QUESTION] “place pages to tail” regress memory read bandwidth about 10% under our test cases
Date: Tue, 30 Nov 2021 11:51:04 +0000 [thread overview]
Message-ID: <3c6349ddd9a34732a251467b7fa4fe93@huawei.com> (raw)
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Hi David,
We met a performance regression(lmbench bw_mmap_rd/bw_mem) on our server with
patch 7fef431be9c9(mm/page_alloc: place pages to tail in __free_pages_core()),
Case A. ./bw_mmap_rd -P 1 512m mmap_only out.file
Case B. ./bw_mem -P 1 512m frd
mode0: IMC Interleave = auto, Channel Interleave = auto, Rank Interleave = auto
without with regression
case A 10535.14 9645.02 8.4%
case B 10526.88 9797.63 6.9%
also we found different memory interleaving have different results
mode1: IMC Interleave = 1-way, Channel Interleave = 2-way, Rank Interleave =2-way
without with regression
case A 10543.01 10643.12 -0.9%
case B 10971.33 10853.99 1%
The 7fef431be9c9 changes the different memory layout, it seems that the issue
is related with memory interleave. But the patch does lead to performance regression.
Any suggestion about this regression?
thanks.
Peng Liu
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next reply other threads:[~2021-11-30 11:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-30 11:51 liupeng (DM) [this message]
2021-11-30 12:37 ` David Hildenbrand
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