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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