Re: [PATCH 03/19] mm: compaction: Add scanned and isolated countersfor compaction

[Rik van Riel]

On 11/06/2012 04:14 AM, Mel Gorman wrote:
> Compaction already has tracepoints to count scanned and isolated pages
> but it requires that ftrace be enabled and if that information has to be
> written to disk then it can be disruptive. This patch adds vmstat counters
> for compaction called compact_migrate_scanned, compact_free_scanned and
> compact_isolated.
>
> With these counters, it is possible to define a basic cost model for
> compaction. This approximates of how much work compaction is doing and can
> be compared that with an oprofile showing TLB misses and see if the cost of
> compaction is being offset by THP for example. Minimally a compaction patch
> can be evaluated in terms of whether it increases or decreases cost. The
> basic cost model looks like this


> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>

Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/