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 Tue, 29 Aug 2017 19:02:23 -0600
Date: Tue, 29 Aug 2017 18:02:09 -0700
From: Haren Myneni <haren@linux.vnet.ibm.com>
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Dan Streetman <ddstreet@ieee.org>, Michael Ellerman <mpe@ellerman.id.au>,
 Herbert Xu <herbert@gondor.apana.org.au>,
 Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
 "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
 mikey@neuling.org, suka@us.ibm.com, Ram Pai <linuxram@us.ibm.com>,
 npiggin@gmail.com, Haren Myneni <hbabu@us.ibm.com>
Subject: Re: [PATCH V3 6/6] crypto/nx: Add P9 NX support for 842 compression
 engine
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On 08/29/2017 02:57 PM, Benjamin Herrenschmidt wrote:
> On Tue, 2017-08-29 at 14:54 -0700, Haren Myneni wrote:
>> Opening send window for each crypto transform (crypto_alloc,
>> compression/decompression, ..., crypto_free) so that does not have to
>> wait for the previous copy/paste complete. VAS will map send and
>> receive windows, and can cache in send windows (up to 128). So I
>> thought using the same send window (per chip) for more requests (say
>> 1000) may be adding overhead.
>>
>> I will make changes if you prefer using 1 send window per chip.  
> 
> Did you check the cost of opening/closing a window ?

No, Not yet. opening / closing happens only during alloc/free, but not for each compression/decompression. Hence used separate send windows. 

Thanks
Haren  
 
> 
> Cheers,
> Ben.
>