RE: [PATCH] Performance Improvement in CRC16 Calculations.

[Jeffrey Lien]

Joe, Doug, Nicolas,
The CONFIG patch change suggested by Joe and Doug makes sense to do.   I'll do some additional testing to verify the performance on my systems.   


Jeff Lien

-----Original Message-----
From: Joe Perches [mailto:joe@xxxxxxxxxxx] 
Sent: Saturday, August 11, 2018 10:06 AM
To: dgilbert@xxxxxxxxxxxx; Nicolas Pitre <nicolas.pitre@xxxxxxxxxx>
Cc: Jeffrey Lien <Jeff.Lien@xxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; linux-crypto@xxxxxxxxxxxxxxx; linux-block@xxxxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx; herbert@xxxxxxxxxxxxxxxxxxx; tim.c.chen@xxxxxxxxxxxxxxx; martin.petersen@xxxxxxxxxx; David Darrington <david.darrington@xxxxxxx>; Jeff Furlong <jeff.furlong@xxxxxxx>
Subject: Re: [PATCH] Performance Improvement in CRC16 Calculations.

On Sat, 2018-08-11 at 02:04 -0700, Joe Perches wrote:
> On Fri, 2018-08-10 at 22:39 -0400, Douglas Gilbert wrote:
> > but below is a copy and paste of a table 27 from draft SBC-4 
> > revision 15 in chapter 4.22.4.4 on page 87.
> 
> The posted code returns the proper crc for each 
> CONFIG_CRYPTO_CRCT10DIF_TABLE_SIZE value from
> 1 to 5 for these arrays.

Jeff, could you please test the suggested patch with your comparison framework again with each CONFIG_CRYPTO_CRCT10DIF_TABLE_SIZE from 1 to 5?

I get on a very limited test framework here:
(runtime average of 10 runs)

1: 4.32
2: 1.86
3: 1.31
4: 1.05
5: 0.99