From: Junchang Wang <junchangwang@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: Question about __alloc_skb() speedup
Date: Sun, 5 Dec 2010 18:56:24 +0800 [thread overview]
Message-ID: <20101205105616.GA4770@Desktop-Junchang> (raw)
In-Reply-To: <1291474058.2806.96.camel@edumazet-laptop>
On Sat, Dec 04, 2010 at 03:47:38PM +0100, Eric Dumazet wrote:
>
>Yes I believe so, pktgen being very specific, but I have few questions :
>
>Is it with SLUB or SLAB ?
I had read your discussion about "net: allocate skbs on local node" in
the list, so SLUB was used.
BTW, what I observed is that network subsystem scales well on NUMA
systems equipped with a single processor(up to six cores), but the
performance didn't scale very well if there are two processors.
I have noticed there are a number of discussions in the list. Are
there any suggestions? I'm very pleasant to do test.
>
>How many buffers in TX ring on you nic (ethtool -g eth0) ?
>
Pre-set maximums:
RX: 4096
RX Mini: 0
RX Jumbo: 0
TX: 4096
Current hardware settings:
RX: 512
RX Mini: 0
RX Jumbo: 0
TX: 512
>What is the datalen value here ? (you prefetch, then advance skb->data)
>
16. But the following skb_push will drawback 14 bytes.
>32 or 64bit kernel ?
>
This is a CentOS 5.5 - 64bit distribution with the latest net-next.
>How many pps do you get before and after patch ?
>
A Intel SR1625 server with two E5530 quad-core processors and a single
ixgbe-based NIC.
Without prefetch: 8.63 Mpps
With prefetch: 9.03 Mpps
Improvement: 4.6%
Thanks.
--Junchang
next prev parent reply other threads:[~2010-12-05 10:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-03 10:14 Question about __alloc_skb() speedup Junchang Wang
2010-12-03 10:50 ` Eric Dumazet
2010-12-04 14:18 ` Junchang Wang
2010-12-04 14:47 ` Eric Dumazet
2010-12-04 14:49 ` Eric Dumazet
2010-12-05 10:56 ` Junchang Wang [this message]
2010-12-05 16:49 ` Eric Dumazet
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