Does anyone has any ideas about this problem?
2008/1/15, 陶捷 TaoJie <[EMAIL PROTECTED]>:
>
> Hi all:
>
> I'm working on revealing system performance now.
> My testing program is an infinite loop. Inside the loop, it will do some
> mathematical opertaions and call function callee(), then go to the next
> loop.
> I install a alarm(30) in the program. It means it will stop after running
> 30 seconds.
> Before calling alarm(30), at the beginning of the main body, it will use
> libkstat to read kstat-cpu-sys record first.
> After the alarm signal raised, in the signal handler, it will re-read the
> kstat-cpu-sys record, and show the difference in this 30 seconds period.
>
> For example, following is output printed on the screen,
> *30.00 secs, 0.00 events per secs
> user=99.7279%, kernel=0.2721%, idle=0.0000%
> per second: intr=308.64, ithr=208.63, syscall=1.80, csw=78.14
> per second: smtx=0.33, srw=0.00
> per second: migr=0.00
> * //Events are some syscalls or some user-defined functions.
>
> In a word, this program looks very like the mpstat.
>
> One of my testcases is running this program with dtrace's fasttrap
> provider, such as:
> dtrace -n 'pid$targer::callee:entry{ ... }' -c my_program
> dtrace -n 'test$target:::callee{ ... }' -c my_program
>
> The output is very strange.
> *30.00 secs, 213099.33 per secs
> user=99.6749%, kernel=0.3251%, idle=0.0000%
> per second: intr=513.15, ithr=312.13, syscall=48.67, csw=87.27
> per second: smtx=0.10, srw=0.00
> per second: migr= 0.00*
>
> In the infinite loop, callee would be called more than 2000000 times. Each
> time it is called, the program would trap into kernel because it is
> monitored by dtrace.
>
> Compared with the program running with no dtrace,
> *30.00 secs, 100628.74 per secs
> user=99.7396%, kernel=0.2604%, idle=0.0000%
> per second: intr=308.89, ithr=208.89, syscall=3.13, csw=73.24
> per second: smtx=0.17, srw=0.00
> per second: migr= 0.00
> *
> No big difference between these 2 kernel time percentages!
>
> I think this is unbelievable! And maybe the answer is microstat accounting
> system cannot log this kind of interrupt.
> Since I try this program on Intel P4 platform. In i86pc, dtrace using "int
> $3" to help the user program to trap into dtrace kernel module.
>
> So, does it means that the mircostat accouting does not work in "int $3"
> and some other cases?
> Am I right?
>
> P.S. I'm using ON build 74.
> Thank you.
>
>
> Kind Regards,
> TJ
>
_______________________________________________
opensolaris-code mailing list
[email protected]
http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
