tty problems in recent head?
Giorgos Keramidas
keramida at ceid.upatras.gr
Sat Nov 29 07:51:45 PST 2008
On Fri, 28 Nov 2008 20:47:00 -0800, "Peter Wemm" <peter at wemm.org> wrote:
> On Fri, Nov 28, 2008 at 8:27 PM, Giorgos Keramidas
> <keramida at ceid.upatras.gr> wrote:
>> Since this part of sched_ule.c hasn't changed in a while
>>
>> REV CHANGE AUTHOR
>> ---------------------------------------------------------------------------------------------------
>> 1848 171482 jeff cpu_switch(td, newtd, mtx);
>> 1849 171482 jeff /*
>> 1850 171482 jeff * We may return from cpu_switch on a different cpu. However,
>> 1851 171482 jeff * we always return with td_lock pointing to the current cpu's
>> 1852 171482 jeff * run queue lock.
>> 1853 171482 jeff */
>> 1854 171482 jeff cpuid = PCPU_GET(cpuid);
>> 1855 171482 jeff tdq = TDQ_CPU(cpuid);
>> 1856 174629 jeff lock_profile_obtain_lock_success(
>> 1857 174629 jeff &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
>> 1858 145256 jkoshy #ifdef HWPMC_HOOKS
>> 1859 145256 jkoshy if (PMC_PROC_IS_USING_PMCS(td->td_proc))
>> 1860 145256 jkoshy PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
>> 1861 145256 jkoshy #endif
>>
>> any ideas why PCPU_GET() might spin like this?
>
> It isn't. The 'info' command is misleading you. It is merely the
> next instruction after returning from cpu_switch(). Something is
> effectively in a yield loop.
Thanks. I went back to 2008-11-16 15:45 +0000 and I can still see xterm
processes stuck after a while. Two potentially useful bits are:
1. My `/etc/make.conf' contained after the last restore from backups:
: # Are these two really safe?
: CFLAGS?= -O2 -fno-strict-aliasing -pipe
: COPTFLAGS?= -O -pipe
:
: #NO_CPU_CFLAGS= # Don't add -march=<cpu> to CFLAGS automatically
: #NO_CPU_COPTFLAGS= # Don't add -march=<cpu> to COPTFLAGS automatically
I commented both out, to see if it changes things. If the same happens
without -O2 optimizations, I'll keep going backwards to see if I can
locate the commit that this started happening.
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