Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-06-05 Thread Andriy Gapon
on 03/06/2011 19:28 Jung-uk Kim said the following: > Unlike Intel, AMD did not guarantee "all TSCs reset to zero with RESET > IPI" before Bulldozer[1]. In fact, I tried to measure deltas between > cores when I started hacking on it using some crude heuristics, > somewhat like the OpenSolaris h

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-06-03 Thread Jung-uk Kim
On Friday 03 June 2011 02:03 am, Andriy Gapon wrote: > on 01/06/2011 23:55 Jung-uk Kim said the following: > > Yes, it's still a work-in-progress. However, I thought it is > > good enough for 9.0 inclusion. BTW, the latest patch is here: > > > > http://people.freebsd.org/~jkim/tsc_smp_test5.diff

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-06-03 Thread Andriy Gapon
on 03/06/2011 14:50 John Baldwin said the following: > On Friday, June 03, 2011 2:03:55 am Andriy Gapon wrote: >>> Consecutive RDTSCs used on a same CPU is always incremental but we >>> cannot 100% guarantee that on two cores, even if TSC is derived from >>> the same clock. I am hoping at least

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-06-03 Thread John Baldwin
On Friday, June 03, 2011 2:03:55 am Andriy Gapon wrote: > > Consecutive RDTSCs used on a same CPU is always incremental but we > > cannot 100% guarantee that on two cores, even if TSC is derived from > > the same clock. I am hoping at least latency difference (I believe > > it's about few tens

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-06-02 Thread Andriy Gapon
on 01/06/2011 23:55 Jung-uk Kim said the following: > Yes, it's still a work-in-progress. However, I thought it is good > enough for 9.0 inclusion. BTW, the latest patch is here: > > http://people.freebsd.org/~jkim/tsc_smp_test5.diff > > FYI, the only meaningful change from the previous versio

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-06-01 Thread Jung-uk Kim
On Wednesday 01 June 2011 01:40 am, Andriy Gapon wrote: > on 31/05/2011 23:16 Jung-uk Kim said the following: > > On Tuesday 31 May 2011 07:18 am, Andriy Gapon wrote: > >> on 24/05/2011 20:56 Jung-uk Kim said the following: > >>> I think it's about time to enable invariant TSC timecounter on > >>>

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-05-31 Thread Andriy Gapon
on 31/05/2011 23:16 Jung-uk Kim said the following: > On Tuesday 31 May 2011 07:18 am, Andriy Gapon wrote: >> on 24/05/2011 20:56 Jung-uk Kim said the following: >>> I think it's about time to enable invariant TSC timecounter on >>> SMP by default. Please see the attached patch. It is also >>> av

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-05-31 Thread Jung-uk Kim
On Tuesday 31 May 2011 07:18 am, Andriy Gapon wrote: > on 24/05/2011 20:56 Jung-uk Kim said the following: > > I think it's about time to enable invariant TSC timecounter on > > SMP by default. Please see the attached patch. It is also > > available from here: > > > > http://people.freebsd.org/~j

Re: [RFC] Enabling invariant TSC timecounter on SMP

2011-05-31 Thread Andriy Gapon
on 24/05/2011 20:56 Jung-uk Kim said the following: > I think it's about time to enable invariant TSC timecounter on SMP by > default. Please see the attached patch. It is also available from > here: > > http://people.freebsd.org/~jkim/tsc_smp_test4.diff > > avg convinced me enough that it sh

[RFC] Enabling invariant TSC timecounter on SMP

2011-05-24 Thread Jung-uk Kim
I think it's about time to enable invariant TSC timecounter on SMP by default. Please see the attached patch. It is also available from here: http://people.freebsd.org/~jkim/tsc_smp_test4.diff avg convinced me enough that it should be an opt-out feature going forward. :-) Comments? Cheers,