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SubjectRe: [PATCH 0/10] Reduce system disruption due to kswapd V2
Hi Zlatko,
On 04/22/2013 02:54 PM, Zlatko Calusic wrote:
> 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/

Thanks Zlatko, I successfully install, could you tell me your options?




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