linux-kernel - Re: [PATCH] Performance Improvement in CRC16 Calculations.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <nycvar.YSQ.7.76.1808101601110.13885@knanqh.ubzr>
Date:   Fri, 10 Aug 2018 16:02:23 -0400 (EDT)
From:   Nicolas Pitre <nicolas.pitre@...aro.org>
To:     Joe Perches <joe@...ches.com>
cc:     Jeff Lien <jeff.lien@....com>, linux-kernel@...r.kernel.org,
        linux-crypto@...r.kernel.org, linux-block@...r.kernel.org,
        linux-scsi@...r.kernel.org, herbert@...dor.apana.org.au,
        tim.c.chen@...ux.intel.com, martin.petersen@...cle.com,
        david.darrington@....com, jeff.furlong@....com
Subject: Re: [PATCH] Performance Improvement in CRC16 Calculations.

On Fri, 10 Aug 2018, Joe Perches wrote:

> On Fri, 2018-08-10 at 14:12 -0500, Jeff Lien wrote:
> > This patch provides a performance improvement for the CRC16 calculations done in read/write
> > workloads using the T10 Type 1/2/3 guard field.  For example, today with sequential write
> > workloads (one thread/CPU of IO) we consume 100% of the CPU because of the CRC16 computation
> > bottleneck.  Today's block devices are considerably faster, but the CRC16 calculation prevents
> > folks from utilizing the throughput of such devices.  To speed up this calculation and expose
> > the block device throughput, we slice the old single byte for loop into a 16 byte for loop,
> > with a larger CRC table to match.  The result has shown 5x performance improvements on various
> > big endian and little endian systems running the 4.18.0 kernel version.
> 
> Thanks.
> 
> This seems a sensible tradeoff for the 4k text size increase.

More like 7.5KB.  Would be best if this was configurable so the small 
version remained available.


Nicolas