On 10/07/2013 06:28 AM, Mel Gorman wrote: > NUMA hinting fault counts and placement decisions are both recorded in the > same array which distorts the samples in an unpredictable fashion. The values > linearly accumulate during the scan and then decay creating a sawtooth-like > pattern in the per-node counts. It also means that placement decisions are > time sensitive. At best it means that it is very difficult to state that > the buffer holds a decaying average of past faulting behaviour. At worst, > it can confuse the load balancer if it sees one node with an artifically high > count due to very recent faulting activity and may create a bouncing effect. > > This patch adds a second array. numa_faults stores the historical data > which is used for placement decisions. numa_faults_buffer holds the > fault activity during the current scan window. When the scan completes, > numa_faults decays and the values from numa_faults_buffer are copied > across. > > Signed-off-by: Mel Gorman <mgor...@suse.de>
Reviewed-by: Rik van Riel <r...@redhat.com> -- All rights reversed -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
