From: Deng-Cheng Zhu <dczhu@mips.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: <davem@davemloft.net>, <therbert@google.com>, <netdev@vger.kernel.org>
Subject: Re: [PATCH] RPS: Sparse connection optimizations
Date: Wed, 2 May 2012 12:16:39 +0800 [thread overview]
Message-ID: <4FA0B527.7020400@mips.com> (raw)
In-Reply-To: <1335931968.22133.47.camel@edumazet-glaptop>
On 05/02/2012 12:12 PM, Eric Dumazet wrote:
> On Wed, 2012-05-02 at 12:08 +0800, Deng-Cheng Zhu wrote:
>
>> Unfortunately, on the Malta platform, NIC irqs are not suitable for SMP
>> IRQ affinity -- they are based on XT-PIC. However, I did do some RPS
>> tests where different CPU masks were assigned to the 2 NICs. And the
>> throughput *WAS* better than that of assigning the same mask to NICs.
>> But the problem addressed in this patch *STILL* exists -- hash indexing
>> causes imbalance across CPUs in the case of sparse connections.
>
> You mean your two NIC irqs are handled by CPU0 and this cant be
> changed ?
>
> That really is bad.
>
>
>
Yes, that's right. It's not IO-APIC enabled. When trying to write values
to /proc/irq/$irqnum/smp_affinity:
echo: write error: Input/output error
Deng-Cheng
prev parent reply other threads:[~2012-05-02 4:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-28 10:10 [PATCH] RPS: Sparse connection optimizations Deng-Cheng Zhu
2012-04-28 11:55 ` Eric Dumazet
2012-05-02 4:08 ` Deng-Cheng Zhu
2012-05-02 4:12 ` Eric Dumazet
2012-05-02 4:16 ` Deng-Cheng Zhu [this message]
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