Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753040AbaF0JB3 (ORCPT ); Fri, 27 Jun 2014 05:01:29 -0400 Received: from mail-wg0-f49.google.com ([74.125.82.49]:36973 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752462AbaF0JB1 (ORCPT ); Fri, 27 Jun 2014 05:01:27 -0400 Message-ID: <53AD32E3.7030405@schaman.hu> Date: Fri, 27 Jun 2014 10:01:23 +0100 From: Zoltan Kiss User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: David Miller CC: steffen.klassert@secunet.com, minipli@googlemail.com, dborkman@redhat.com, tgraf@suug.ch, joe@perches.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org Subject: Re: [PATCH net-next] pktgen: Fill the payload optionally with a pattern References: <1403642415-9560-1-git-send-email-zoltan.kiss@citrix.com> <20140625.175417.231387590142784357.davem@davemloft.net> In-Reply-To: <20140625.175417.231387590142784357.davem@davemloft.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/06/14 01:54, David Miller wrote: > From: Zoltan Kiss > Date: Tue, 24 Jun 2014 21:40:15 +0100 > >> Introduces a new flag called PATTERN, which puts a non-periodic, predicatble >> pattern into the payload. This was useful to reproduce an otherwise intermittent >> bug in xen-netback [1], where checksum checking doesn't help. >> The pattern is a repetition of " %lu", a series of increasing numbers divided by >> space. The value of the number is the size of the preceding payload area. E.g. >> " 1 3 5"..." 1000 1005 1010" >> If the pattern is used, every frag will have its own page, unlike before, so it >> needs more memory. >> >> [1] 5837574: xen-netback: Fix grant ref resolution in RX path >> >> Signed-off-by: Zoltan Kiss > You are changing the page allocation strategy regardless of the pattern > setting, this is undesirable. > > It may be significantly faster to use the same page for all the frags, > and this is absolutely critical for pktgen usage where every nanosecond > of performance counts. If the PATTERN flag is not used, it always using the pages[0] page, so it falls back to the original way. Zoli -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/