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Re: [openib-general] Re: LLTX and netif_stop_queue

To: Eric Lemoine <eric.lemoine@xxxxxxxxx>
Subject: Re: [openib-general] Re: LLTX and netif_stop_queue
From: Grant Grundler <iod00d@xxxxxx>
Date: Mon, 3 Jan 2005 09:12:27 -0800
Cc: Roland Dreier <roland@xxxxxxxxxxx>, netdev@xxxxxxxxxxx, hadi@xxxxxxxxxx, Andi Kleen <ak@xxxxxxx>, openib-general@xxxxxxxxxx, Patrick McHardy <kaber@xxxxxxxxx>, "David S. Miller" <davem@xxxxxxxxxxxxx>
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On Mon, Jan 03, 2005 at 06:07:00PM +0100, Eric Lemoine wrote:
> If I understand correctly, LLTX aims at avoiding cache misses on lock
> variables (because of cacheline bouncing). So the effect of LLTX
> should increase as the number of CPUs not sharing the same cache
> increases. And two CPUs might not be enough...

Cacheline bouncing usually starts to show up with > 4 CPUs (ie 8 or more).
Some workloads that Jamal cares about (routing) only need 2 cpus.

grant

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