Great stuff Ingo!
> now that new-year's parties are over things are getting boring again. For
> those who want to see and perhaps even try something more complex, i'm
> announcing this patch that is a pretty radical rewrite of the Linux
> scheduler for 2.5.2-pre6:
Good timing :) We were just looking at an application that hit sched_yield
heavily on a large SMP machine (dont have the source so fixing the
symptoms not the cause). Performance was pretty bad with the standard
We managed to get a 4 way ppc64 machine to boot, but unfortunately the
18 way hung somewhere after smp initialisation and before execing
init. More testing to come :)
Is the idle loop optimisation (atomic exchange -1 into need_resched
to avoid IPI) gone forever?
Is my understanding of this right?:
#define BITMAP_SIZE (MAX_RT_PRIO/8+1)
You have an bitmap of size MAX_RT_PRIO+1 (actually I think you have one too
many +1 here :) and you zero the last bit to terminate it. You use
find_first_zero_bit to search the entire priority list and
sched_find_first_zero_bit to search only the first MAX_PRIO (64) bits.
> the SMP load-balancer can be extended/switched with additional parallel
> computing and cache hierarchy concepts: NUMA scheduling, multi-core CPUs
> can be supported easily by changing the load-balancer. Right now it's
> tuned for my SMP systems.
It will be interesting to test this on our HMT hardware.
> - the SMP idle-task startup code was still racy and the new scheduler
> triggered this. So i streamlined the idle-setup code a bit. We do not call
> into schedule() before all processors have started up fully and all idle
> threads are in place.
I like this cleanup, it pushes more stuff out the arch specific code
> another benchmark measures sched_yield() performance. (which the pthreads
> code relies on pretty heavily.)
Can you send me this benchmark and I'll get some more results :)
I dont think pthreads uses sched_yield on spinlocks any more, but there
seems to be enough userspace code that does.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to email@example.com
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Jan 07 2002 - 21:00:24 EST