RE: [patch] rearrange kioctx and aio_ring_info

From: Chen, Kenneth W
Date: Thu Oct 12 2006 - 20:21:13 EST


Dave Jones wrote on Thursday, October 12, 2006 5:04 PM
> On Thu, Oct 12, 2006 at 04:25:54PM -0700, Chen, Kenneth W wrote:
> > The following patch is result of our kernel data latency analysis on a
> > large database setup (128 logical CPU, 1 TB memory, a couple thousand
> > disks). The analysis is done at an individual cache line level through
> > hardware performance monitor unit. What we did essentially is to collect
> > data access latency on every kernel memory address and look for top 50
> > longest average access latency. The hardware performance unit also keeps
> > track of instruction address for each collected data access. This allows
> > us to further associate each of the top 50 cache lines to instruction
> > sequences that caused long latency.
>
> Do you have performance numbers of before/after this change ?


Not yet, I just queued up experiment on our internal benchmark setup. I posted
the patch here to get some early discussion on how to attack the problem.
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