Re: exit timing analysis v1 - comments&discussions welcome

[Hollis Blanchard <hollisb@us.ibm.com>]

On Wed, 2008-09-24 at 11:24 +0200, Christian Ehrhardt wrote:
>                      count      min         max             
> sum            avg        stddev     time%
>     EMULINST     6,423,699       12     247,582      91,732,705        
> 14.2804       241.200     45.36
>     ITLBVIRT     1,777,242       21     264,257      47,116,557        
> 26.5111       286.040     23.30
>     DTLBVIRT     1,544,241       22     263,947      41,765,447        
> 27.0459       218.997     20.65

(The max here is of course when the guest was de-scheduled in favor of
another host process.)

I think it's interesting that the min instruction emulation time is 12
usecs. In fact, our "null" exits where we do almost no processing (ISI,
DSI, syscall) are 11 usecs, which suggests we have a problem with
interrupt handler overhead (for all exit types).

-- 
Hollis Blanchard
IBM Linux Technology Center