Re: [Patch 1/4] Delay accounting: Initialization

Peter Chubb
2005-11-16T01:53:11Z

>>>>> "Shailabh" == Shailabh Nagar <nagar@watson.ibm.com> writes:

Shailabh> Peter Chubb wrote:
>>>>>>> "Andrew" == Andrew Morton <akpm@osdl.org> writes:
>>
Andrew> Shailabh Nagar <nagar@watson.ibm.com> wrote:
>>
>>>> + *ts = sched_clock();
>>
Andrew> I'm not sure that it's kosher to use sched_clock() for
Andrew> fine-grained timestamping like this. Ingo had issues with it
Andrew> last time this happened?
>> It wasn't Ingo, it was Andi Kleen... for my Microstate Accounting
>> patches, which do very similar things to Shailabh's patchsetm, but
>> using /proc and a system call instead (following Solaris's lead)
>>

Shailabh> Were these the comments from Andi to which you refer:
Shailabh> http://www.uwsg.indiana.edu/hypermail/linux/kernel/0503.1/1237.html

Shailabh> The objections to microstate overhead seemed to stem from
Shailabh> the syscall overhead, not use of sched_clock() per se.

The objection was to the use of rdtsc (which is sched_clock() on
platforms that have rdtsc) in fastpaths.

Anyway, I think it's time to repost the microstate patches.
--
Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au
The technical we do immediately, the political takes *forever*