Re: rt14: strace -> migrate_disable_atomic imbalance

Mike Galbraith
2011-09-22T14:05:34Z

On Thu, 2011-09-22 at 15:42 +0200, Mike Galbraith wrote:
> On Thu, 2011-09-22 at 14:09 +0200, Peter Zijlstra wrote:
> > On Thu, 2011-09-22 at 13:55 +0200, Mike Galbraith wrote:
> > > On Thu, 2011-09-22 at 12:00 +0200, Peter Zijlstra wrote:
> > >
> > > > OK, this one seems to be better.. But its quite vile, not sure I
> > > > actually like it anymore.
> > >
> > > Well, seemed to work, but I see there's a v3 now.
> >
> > Yeah, just posted it for completeness, not sure its actually going
> > anywhere since its slower than the current code (although its hard to
> > say with the results changing from reboot to reboot), and its still
> > quite ugly..
>
> Hm. Stracing this proglet will soon leave it stuck forever unless the
> timer is left running. Virgin rt14 does the same though...
>
> strace ./jitter -c 3 -p 99 -f 1000 -t 10 -r
>
> rt_sigtimedwait([], NULL, NULL, 8) = 64
> timer_settime(0x1, TIMER_ABSTIME, {it_interval={0, 0}, it_value={0, 0}}, NULL) = 0
> timer_settime(0x1, TIMER_ABSTIME, {it_interval={0, 0}, it_value={1316698141, 166759038}}, NULL) = 0
> rt_sigtimedwait([], NULL, NULL, 8) = 64
> timer_settime(0x1, TIMER_ABSTIME, {it_interval={0, 0}, it_value={0, 0}}, NULL) = 0
> timer_settime(0x1, TIMER_ABSTIME, {it_interval={0, 0}, it_value={1316698141, 167822701}}, NULL) = 0
> rt_sigtimedwait([], NULL, NULL, 8) = 64
> timer_settime(0x1, TIMER_ABSTIME, {it_interval={0, 0}, it_value={0, 0}}, NULL) = 0
> timer_settime(0x1, TIMER_ABSTIME, {it_interval={0, 0}, it_value={1316698141, 168887375}}, NULL) = 0
> --- SIGRT_32 (Real-time signal 30) @ 0 (0) ---
> rt_sigreturn(0x40) = 0
> rt_sigtimedwait([], NULL, NULL, 8^C <unfinished ...>

I thought it was RT specific, but it's not after all, a 3.0.4 distro
desktop (preempt) kernel did the same after a bit.

-Mike