Messages in this thread | | | Date | Mon, 22 Apr 2013 14:43:35 +0800 | From | Simon Jeons <> | Subject | Re: [PATCH 0/10] Reduce system disruption due to kswapd V2 |
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Hi Zlatko, On 04/22/2013 02:37 PM, Zlatko Calusic wrote: > On 12.04.2013 22:07, Zlatko Calusic wrote: >> On 12.04.2013 21:40, Mel Gorman wrote: >>> On Thu, Apr 11, 2013 at 10:55:13PM +0200, Zlatko Calusic wrote: >>>> On 09.04.2013 13:06, Mel Gorman wrote: >>>> <SNIP> >>>> >>>> - The only slightly negative thing I observed is that with the patch >>>> applied kswapd burns 10x - 20x more CPU. So instead of about 15 >>>> seconds, it has now spent more than 4 minutes on one particular >>>> machine with a quite steady load (after about 12 days of uptime). >>>> Admittedly, that's still nothing too alarming, but... >>>> >>> >>> Would you happen to know what circumstances trigger the higher CPU >>> usage? >>> >> >> Really nothing special. The server is lightly loaded, but it does enough >> reading from the disk so that pagecache is mostly populated and page >> reclaiming is active. So, kswapd is no doubt using CPU time gradually, >> nothing extraordinary. >> >> When I sent my reply yesterday, the server uptime was 12 days, and >> kswapd had accumulated 4:28 CPU time. Now, approx 24 hours later (13 >> days uptime): >> >> root 23 0.0 0.0 0 0 ? S Mar30 4:52 >> [kswapd0] >> >> I will apply your v3 series soon and see if there's any improvement wrt >> CPU usage, although as I said I don't see that as a big issue. It's >> still only 0.013% of available CPU resources (dual core CPU). >> > > JFTR, v3 kswapd uses about 15% more CPU time than v2. 2:50 kswapd CPU > time after 6 days 14h uptime. > > And find attached another debugging graph that shows how ANON pages > are privileged in the ZONE_NORMAL on a 4GB machine. Take notice that > the number of pages in the ZONE_DMA32 is scaled (/5) to fit the graph > nicely. >
Could you tell me how you draw this picture?
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