Re: performance trouble

[Avi Kivity <avi@redhat.com>]

What's up with the cc list?


On 01/31/2012 07:15 PM, David Cure wrote:
> Le Mon, Jan 30, 2012 at 07:21:20PM +0200, Avi Kivity ecrivait :
> > 
> > Start with top and vmstat to see if the cpu or I/O are the bottleneck
>
> 	with top at the kvm layer, the VM take 50% of CPU (the physical
> box have 16 real cores-not HT- : AMD Opteron 6134).
> 	one result of vmstat :
>
> procs -----------memory---------- ---swap-- -----io---- -system--
> ----cpu----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy
> id wa
>  5  0      0 9904544  19612 195440    0    0     0    11    1    0  6  5
> 88  0
>
> 	and I run it 1H and the result is always the same (just free
> result change time to time).

Running vmstat with no arguments gives the average for all uptime.  It's
meaningless.  Run 'vmstat 1'.

How many vcpus are there in total (over all guests)?

What does top show?

>
> > (also helpful to run the Windows performance monitor in the guest).  If
>
> 	between the start of the function and the response, the are no
> performance pic or something like that in Windows.
>
> 	What we can see : 
> 	o we start the function, 
> 	o we see network communication with the database server during 
> ~3/4s 
> 	o after nothing during 10s before display the result
>
>

That's really strange.  No network traffic/cpu/block I/O?

What do 'vmstat 1' and 'top -d 1' say during this?

-- 
error compiling committee.c: too many arguments to function