Messages in this thread | | | Date | Mon, 22 Apr 2013 08:54:24 +0200 | From | Zlatko Calusic <> | Subject | Re: [PATCH 0/10] Reduce system disruption due to kswapd V2 |
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On 22.04.2013 08:43, Simon Jeons wrote: > 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? >
It's a home made server monitoring system. I just added the code needed to graph the size of active + inactive LRU lists, per zone and per type. Check out http://oss.oetiker.ch/rrdtool/
-- Zlatko
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