From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Jeff Lien <jeff.lien@wdc.com>
Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
herbert@gondor.apana.org.au, tim.c.chen@linux.intel.com,
martin.petersen@oracle.com, david.darrington@wdc.com,
jeff.furlong@wdc.com
Subject: Re: [PATCH] Performance Improvement in CRC16 Calculations.
Date: Sat, 11 Aug 2018 11:36:20 -0400 [thread overview]
Message-ID: <yq1in4gq5jf.fsf@oracle.com> (raw)
In-Reply-To: <1533928331-21303-1-git-send-email-jeff.lien@wdc.com> (Jeff Lien's message of "Fri, 10 Aug 2018 14:12:11 -0500")
Jeff,
> 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.
The reason I went with a simple slice-by-one approach was that the
larger tables had a negative impact on the CPU caches. So while
slice-by-N numbers looked better in synthetic benchmarks, actual
application performance started getting affected as the tables grew
larger.
These days we obviously use the hardware-accelerated CRC calculation so
the software table approach mostly serves as a reference
implementation. But given your big vs. little endian performance
metrics, I'm assuming you guys are focused on embedded processors
without support for CRC acceleration?
I have no problem providing a choice for bigger tables. My only concern
is that the selection heuristics need to be more than one-dimensional.
Latency and cache side effects are often more important than throughput.
At least on the initiator side.
Also, I'd like to keep the original slice-by-one implementation for
reference purposes.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2018-08-11 15:36 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-10 19:12 [PATCH] Performance Improvement in CRC16 Calculations Jeff Lien
2018-08-10 19:23 ` Joe Perches
2018-08-10 20:02 ` Nicolas Pitre
2018-08-11 0:11 ` Joe Perches
2018-08-11 0:34 ` Nicolas Pitre
2018-08-11 2:39 ` Douglas Gilbert
2018-08-11 9:04 ` Joe Perches
2018-08-11 15:06 ` Joe Perches
2018-08-13 18:41 ` Jeffrey Lien
2018-08-13 3:36 ` Douglas Gilbert
2018-08-13 4:29 ` Joe Perches
2018-08-10 20:00 ` Nicolas Pitre
2018-08-10 20:16 ` Eric Biggers
2018-08-16 14:02 ` Jeffrey Lien
2018-08-16 14:22 ` Douglas Gilbert
2018-08-16 15:41 ` Christophe LEROY
2018-08-16 17:38 ` Douglas Gilbert
2018-08-17 3:20 ` Martin K. Petersen
2018-08-16 15:47 ` Christophe LEROY
2018-08-10 20:56 ` Douglas Gilbert
2018-08-11 15:36 ` Martin K. Petersen [this message]
2018-08-11 16:35 ` Joe Perches
2018-08-22 1:40 ` Martin K. Petersen
2018-08-22 6:20 ` Christoph Hellwig
2018-08-24 15:32 ` Jeffrey Lien
2018-08-24 15:39 ` Ard Biesheuvel
2018-08-24 16:29 ` Martin K. Petersen
2018-08-24 17:38 ` Ard Biesheuvel
2018-08-24 21:46 ` Martin K. Petersen
2018-08-24 21:54 ` Ard Biesheuvel
2018-08-24 22:12 ` Martin K. Petersen
2018-08-25 6:12 ` Herbert Xu
2018-08-26 2:35 ` Martin K. Petersen
2018-08-26 2:40 ` [PATCH 1/4] crypto: Introduce notifier for new crypto algorithms Martin K. Petersen
2018-08-26 2:40 ` [PATCH 2/4] crc-t10dif: Pick better transform if one becomes available Martin K. Petersen
2018-08-27 6:13 ` Herbert Xu
2018-08-26 2:40 ` [PATCH 3/4] crc-t10dif: Allow current transform to be inspected in sysfs Martin K. Petersen
2018-08-26 2:40 ` [PATCH 4/4] block: Integrity profile init function to trigger module loads Martin K. Petersen
2018-08-26 8:22 ` Ard Biesheuvel
2018-08-26 13:30 ` Martin K. Petersen
2018-08-26 13:44 ` Ard Biesheuvel
2018-08-26 13:48 ` Martin K. Petersen
2018-08-27 6:09 ` [PATCH 1/4] crypto: Introduce notifier for new crypto algorithms Herbert Xu
2018-08-30 14:57 ` Martin K. Petersen
2018-08-30 15:00 ` [PATCH v2 1/3] " Martin K. Petersen
2018-08-30 15:00 ` [PATCH v2 2/3] crc-t10dif: Pick better transform if one becomes available Martin K. Petersen
2018-08-30 15:00 ` [PATCH v2 3/3] crc-t10dif: Allow current transform to be inspected in sysfs Martin K. Petersen
2018-08-31 17:17 ` [PATCH v2 1/3] crypto: Introduce notifier for new crypto algorithms Jeffrey Lien
2018-09-04 5:21 ` Herbert Xu
2018-09-04 13:30 ` Torsten Duwe
2018-08-24 16:30 ` [PATCH] Performance Improvement in CRC16 Calculations Martin K. Petersen
2018-08-13 4:44 ` Chaitanya Kulkarni
2018-08-13 11:45 ` David Laight
2018-08-13 13:50 ` David Laight
2018-08-13 22:44 ` Tim Chen
2018-08-15 12:51 ` Jeffrey Lien
2018-08-15 18:31 ` Pavel Machek
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