* Bosko Milekic <[EMAIL PROTECTED]> [010807 14:51] wrote:
>
> On Tue, Aug 07, 2001 at 12:19:01PM -0700, Matt Dillon wrote:
> > Cache line invalidation does not require an IPI. TLB
> > shootdowns require IPIs. TLB shootdowns are unrelated to
> > interrupt threads, they only occur when shared mmu mappings
> > change. Cache line invalidation can waste cpu cycles --
> > when cache mastership changes occur between cpus due to
> > threads being switched between cpus. I consider this a
> > serious problem in -current.
>
> I don't think it's fair to consider this a serious problem seeing as
> how, as far as I'm aware, we've intended to eventually introduce code that will
> favor keeping threads running on one CPU on that same CPU as long as it is
> reasonable to do so (which should be most of the time).
> I think after briefly discussing with Alfred on IRC that Alfred has
> some CPU affinity patches on the way, but I'm not sure if they address
> thread scheduling with the above intent in mind or if they merely introduce
> an _interface_ to bind a thread to a single CPU.
They do both. :) You can bind a process to a runqueue _and_ at the
same time as long as a process on another CPU doesn't have a much
higher priority we'll take from our local pool.
Basically we give processes that last ran on our own CPU a false
priority boost.
http://people.freebsd.org/~alfred/bind_cpu.diff
+ cpu = PCPU_GET(cpuid);
+ pricpu = runq_findbit(&runqcpu[cpu]);
+ pri = runq_findbit(rq);
+ CTR2(KTR_RUNQ, "runq_choose: pri=%d cpupri=%d", pri, pricpu);
+ if (pricpu != -1 && (pricpu < pri || pri == -1)) {
+ pri = pricpu;
+ rqh = &runqcpu[cpu].rq_queues[pri];
+ } else if (pri != -1) {
+ rqh = &rq->rq_queues[pri];
+ } else {
+ CTR1(KTR_RUNQ, "runq_choose: idleproc pri=%d", pri);
+ return (PCPU_GET(idleproc));
+ }
+ p = TAILQ_FIRST(rqh);
Actually I think this patch is stale, it doesn't have
the priority boost, but basically you can put it in the
if (pricpu != -1 && (pricpu < pri || pri == -1)) {
clause sort of like this:
if (pricpu != -1 && (pricpu - FUDGE < pri || pri == -1)) {
Where FUDGE is the priority boost you want to give local processes.
--
-Alfred Perlstein [[EMAIL PROTECTED]]
Ok, who wrote this damn function called '??'?
And why do my programs keep crashing in it?
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