Heavy system load by pagedaemon

Mike Silbersack silby at silby.com
Fri May 12 16:28:49 UTC 2006

On Fri, 12 May 2006, Iasen Kostov wrote:

> On Fri, 2006-05-12 at 10:27 -0500, Mike Silbersack wrote:
>> Can you provide instructions on how to create a testbench that exhibits
>> these same problems?  Can eAccelerator + PHP + Apache + some simple script
>> + apachebench do the trick?
> 	Nope, apache probaly needs to use many pages of shared memory to
> exhaust the PV Entries (as I understand it). eAccelerator uses shm when
> it has something to put there and most porbably apache does the same. So
> I think You'll need a lot of different scripts (and many apache
> processes) to make eAccelerator cache them and probaly some other media
> to make apache use shm on it own (I'm realy not sure how apache uses
> shared memory but it probably does because this problem apears when
> people are using forking apache).

Well, let me restate what I said above.  If nobody else is running into 
this, nobody else will be motivated to fix it.  On the other hand, if you 
put in the time to figure out how others can reproduce it, others then 
will be able to try to help fixing it.  If you don't show a to reproduce 
it, there's no way it can be fixed.

> 	That's realy nice to hear. Interesting thing is that:
> sysctl vm.zone | grep PV
> PV ENTRY:         48,  5114880, 4039498, 564470, 236393602
> PV Entry's size is 48 here which is even worst than 28 case ... :)
> Regards.

Ah, I was quoting the i386 change.  On amd64, he reduced it from 48 bytes 
to 24 bytes. :)

Mike "Silby" Silbersack

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