On Fri, Sep 04 2009, Richard Kennedy wrote: > Reducing the number of times balance_dirty_pages calls global_page_state > reduces the cache references and so improves write performance on a > variety of workloads. > > 'perf stats' of simple fio write tests shows the reduction in cache > access. > Where the test is fio 'write,mmap,600Mb,pre_read' on AMD AthlonX2 with > 3Gb memory (dirty_threshold approx 600 Mb) > running each test 10 times, dropping the fasted & slowest values then > taking > the average & standard deviation > > average (s.d.) in millions (10^6) > 2.6.31-rc8 648.6 (14.6) > +patch 620.1 (16.5) This patch looks good to me, I have workloads too here where up to 10% of the time is spent in balance_dirty_pages() because of this. I'll give this patch a go on the box and test in question tomorrow, but it looks promising. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
