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Date:      Wed, 22 Mar 2017 22:31:39 +0100
From:      Ben RUBSON <ben.rubson@gmail.com>
To:        svn-src-all@freebsd.org
Subject:   Re: svn commit: r313006 - in head: sys/conf sys/libkern sys/libkern/x86 sys/sys tests/sys/kern
Message-ID:  <91BB426D-2F26-4368-8A2D-420844A067D4@gmail.com>
In-Reply-To: <CAG6CVpWwZhMAsVB%2Bp-N0fMVOzzQSRaYonEfE-4Z6gv%2BLGuRn9w@mail.gmail.com>
References:  <201701310326.v0V3QW30024375@repo.freebsd.org> <20170202184819.GP2092@kib.kiev.ua> <20170203062806.A2690@besplex.bde.org> <CAG6CVpV8fqMd82hjYoyDfO3f5P-x6%2B0OJDoQHtqXqY_tfWtZsA@mail.gmail.com> <20170228121335.Q2733@besplex.bde.org> <CAG6CVpWwZhMAsVB%2Bp-N0fMVOzzQSRaYonEfE-4Z6gv%2BLGuRn9w@mail.gmail.com>

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> On 01 Mar 2017, at 21:57, Conrad Meyer <cem@freebsd.org> wrote:
>=20
> Hi Bruce,
>=20
> On my laptop (Intel(R) Core(TM) i5-3320M CPU =E2=80=94 Ivy Bridge) I =
still see
> a little worse performance with this patch.

Hi Bruce & Conrad,

I gave both patches a try.
It's a real use case, iSCSI throughput.
Both target and initiator running FreeBSD 11, both patched.

I read 100 times 10G from the same raw SSD device.
Results in MB/s.
(top10 is the average of the 10 higher values)

# Without CRC32 :
average : 300.3
std dev :   3.9
top10   : 308.6
max     : 311.4

# With software CRC32 :
average : 197.6
std dev :   6.5
top10   : 204.2
max     : 204.9

# With Conrad CRC32 :
average : 282.4
std dev :   9.1
top10   : 292.9
max     : 293.3

# With Bruce CRC32 :
average : 278.4
std dev :   7.8
top10   : 290.8
max     : 292.5

The difference between the 2 patches is let's say almost non =
significant.
CPU on both sides: Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz

Ben




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