Re: [PATCH] poll: Avoid extra wakeups in select/poll

From: Ingo Molnar
Date: Wed Apr 29 2009 - 05:24:21 EST



* Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:

> > Seems that this is a virtuous patch even though Christoph is struggling
> > a bit to test it?
>
> The main drawback is that the select/poll data structures will get
> larger. That could cause regression in theory. [...]

Current size of struct poll_table_entry is 0x38 on 64-bit kernels.
Adding the key will make it 0x40 - which is not only a power of two
but also matches cache line size on most modern CPUs.

So the size of this structure is ideal now and arithmetics on the
poll table have become simpler as well.

So the patch has my ack:

Acked-by: Ingo Molnar <mingo@xxxxxxx>

Ingo
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