Messages in this thread | | | Date | Wed, 30 Apr 2003 16:59:14 -0700 | From | Andrew Morton <> | Subject | Re: must-fix list for 2.6.0 |
| |
viro@parcelfarce.linux.theplanet.co.uk wrote: > > On Wed, Apr 30, 2003 at 04:21:08PM -0700, Andrew Morton wrote: > > menu if there was a kernel build happening at the same time. That is just > > utterly broken, so if we're going to leave the sched.c code as-is then we > > *require* that all applications be updated to not spin on sched_yield. > > Excuse me, but WTF do they spin on the sched_yield() in the first place? > _That_ sounds like utterly broken...
I think it's happening down inside the old linuxthreads library. No idea who, what, where or why.
There are quite a few places in the kernel which do it, too. Usually when waiting for memory to come free. These are being gradually removed, in favour of blk_congestion_wait() calls.
That leaves behind the very performance-critical sched_yield() in ext3 transaction batching. That was designed to allow other processes to join a transaction before the calling one closes the transaction. With the new yield() it was causing horrid starvation and was lamely replaced with a schedule(). It needs to be resurrected for real, but I'm not sure how. Probably just a sleep(0.01).
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |