Re: [PATCH 4/4] tracing, page-allocator: Add a postprocessing script for page-allocator-related ftrace events

Rik van Riel
2009-08-04T18:28:40Z

Andrew Morton wrote:
> On Tue, 4 Aug 2009 19:12:26 +0100 Mel Gorman <mel@csn.ul.ie> wrote:
>
>> This patch adds a simple post-processing script for the page-allocator-related
>> trace events. It can be used to give an indication of who the most
>> allocator-intensive processes are and how often the zone lock was taken
>> during the tracing period. Example output looks like
>>
>> find-2840
>> o pages allocd = 1877
>> o pages allocd under lock = 1817
>> o pages freed directly = 9
>> o pcpu refills = 1078
>> o migrate fallbacks = 48
>> - fragmentation causing = 48
>> - severe = 46
>> - moderate = 2
>> - changed migratetype = 7
>
> The usual way of accumulating and presenting such measurements is via
> /proc/vmstat. How do we justify adding a completely new and different
> way of doing something which we already do?

Mel's tracing is more akin to BSD process accounting,
where these statistics are kept on a per-process basis.

Nothing in /proc allows us to see statistics on a per
process basis on process exit.

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