From: Zoltan Kiss <zoltan.kiss@schaman•hu>
To: David Miller <davem@davemloft•net>
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
Date: Fri, 27 Jun 2014 10:01:23 +0100 [thread overview]
Message-ID: <53AD32E3.7030405@schaman.hu> (raw)
In-Reply-To: <20140625.175417.231387590142784357.davem@davemloft.net>
On 26/06/14 01:54, David Miller wrote:
> From: Zoltan Kiss <zoltan.kiss@citrix•com>
> 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 <zoltan.kiss@citrix•com>
> 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
next prev parent reply other threads:[~2014-06-27 9:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-24 20:40 [PATCH net-next] pktgen: Fill the payload optionally with a pattern Zoltan Kiss
2014-06-24 20:41 ` [PATCH net-next v2] " Zoltan Kiss
2014-06-26 0:54 ` [PATCH net-next] " David Miller
2014-06-27 9:01 ` Zoltan Kiss [this message]
2014-06-27 19:30 ` David Miller
2014-06-27 20:22 ` Zoltan Kiss
-- strict thread matches above, loose matches on Subject: below --
2014-06-24 14:42 Zoltan Kiss
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