From: Jan Kiszka <jan.kiszka@siemens.com>
To: "Ouyang, Changchun" <changchun.ouyang@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] vhost-switch example: huge memory need and CRC off-loading issue
Date: Sat, 8 Aug 2015 09:17:51 +0200 [thread overview]
Message-ID: <55C5AD1F.9020902@siemens.com> (raw)
In-Reply-To: <F52918179C57134FAEC9EA62FA2F962511C6E9FB@shsmsx102.ccr.corp.intel.com>
On 2015-08-08 02:39, Ouyang, Changchun wrote:
>
>
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jan Kiszka
>> Sent: Saturday, August 8, 2015 1:31 AM
>> To: dev@dpdk.org
>> Subject: [dpdk-dev] vhost-switch example: huge memory need and CRC off-
>> loading issue
>>
>> Hi again,
>>
>> two findings in the vhost-switch example code that can cause grey hair for
>> starters:
>>
>> - MAX_QUEUES of 512 causes pretty high memory need for the application
>> (something between 1 and 2G) - is that really needed? I'm now running
>> with 32, and I'm able to get away with 256M. Can we tune this
>> default?
>
> Don't think we need change default just because your platform is 32,
> Well, my platform is 128, other platform may have other value, :-)
Then let's make it configurable or explore the actual device needs
before allocating the buffer. The impact on memory consumption is way
too big to hard-code this, specifically as this is per physical port IIUC.
>
>>
>> - hw_strip_crc is set to 0, but either the igb driver or the ET2 quad
>> port adapter I'm using is ignoring this. It does strip the CRC, so
>
> Igb and ET2 should NOT ignore it.
Well, they do not listen to us. What can I do to debug this?
According to eth_igb_rx_init, hw_strip_crc affects E1000_RCTL_SECRC in
the receiver control registers, and debugging confirms this (the bit is
unset in all E1000_RCTL accesses). But there is still no CRC at the end
of received packets. Possibly, there is some other knob that controls
CRC stripping?
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2015-08-08 7:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-07 17:31 Jan Kiszka
2015-08-08 0:39 ` Ouyang, Changchun
2015-08-08 7:17 ` Jan Kiszka [this message]
2015-08-09 8:56 ` Thomas Monjalon
2015-08-10 1:10 ` Ouyang, Changchun
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