From: P@draigBrady.com
To: satya srikanth <satyasrikanth2001@yahoo.com>
Cc: netdev@oss.sgi.com
Subject: Re: Xeon smp performance
Date: Mon, 08 Mar 2004 15:15:30 +0000 [thread overview]
Message-ID: <404C8E12.4060403@draigBrady.com> (raw)
In-Reply-To: <20040308132354.77437.qmail@web21101.mail.yahoo.com>
satya srikanth wrote:
> Hi,
> I am writing a simple sniffer program that will
> sniff packets in a gigabit network. I am using a dual
> processor 2 GHz Xeon processor with one Intel Pro-1000
> desktop adapter, running 2.4.20-8smp linux.
> I found that for all packet sizes and network
> bandwidth, 2.4.20-8 uniprocessor version that uses
> only one processor is performing better than
> 2.4.20-8smp using two processors in terms of packet
> drops and CPU utilization. Each processor in smp is
> utilizing more CPU than one processor in uni-processor
> case. What is the reason for this peculiar behaviour?
> Is it possible for me to use the power of second
> processor without adding more NICs. Will I face
> similar problems with 2.6 also? Anybody familiar with
> these please help me out.
That matches my experience. My chipset was Intel E7501
with 2 intel pro-1000 adapters. I used the base 2.4.20 kernel
with latest intel drivers.
I had 2 processes capturing packets and noticed that
2 CPUs is 7% slower than one CPU. Note I was using a non SMP
kernel for the one CPU case.
I'm going to have to look into improving this soon.
First I'm going to look at IRQ and process affinity.
Pádraig.
prev parent reply other threads:[~2004-03-08 15:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-08 13:23 Xeon smp performance satya srikanth
2004-03-08 15:15 ` P [this message]
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