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On Apr 21, 2007, at 12:42:41, William Lee Irwin III wrote: > On Sat, 21 Apr 2007, Willy Tarreau wrote: >>> If you remember, with 50/50, I noticed some difficulties to fork >>> many processes. I think that during a fork(), the parent has a >>> higher probability of forking other processes than the child. So >>> at least, we should use something like 67/33 or 75/25 for parent/ >>> child. > > On Sat, Apr 21, 2007 at 09:34:07AM -0700, Linus Torvalds wrote: >> It would be even better to simply have the rule: >> - child gets almost no points at startup >> - but when a parent does a "waitpid()" call and blocks, it will >> spread out its points to the childred (the "vfork()" blocking is >> another case that is really the same). >> This is a very special kind of "priority inversion" logic: you >> give higher priority to the things you wait for. Not because of >> holding any locks, but simply because a blockign waitpid really is >> a damn big hint that "ok, the child now works for the parent". > > An in-kernel scheduler API might help. void yield_to(struct > task_struct *)? > > A userspace API might be nice, too. e.g. int sched_yield_to(pid_t). It might be nice if it was possible to actively contribute your CPU time to a child process. For example: int sched_donate(pid_t pid, struct timeval *time, int percentage); Maybe a way to pass CPU time over a UNIX socket (analogous to SCM_RIGHTS), along with information on what process/user passed it That would make it possible to really fix X properly on a local system. You could make the X client library pass CPU time to the X server whenever it requests a CPU-intensive rendering operation. Ordinarily X would nice all of its client service threads to +10, but when a client passes CPU time to its thread over the socket, then its service thread temporarily gets the scheduling properties of the client. I'm not a scheduler guru, but that's what makes the most sense from an application-programmer point of view. Cheers, Kyle Moffett - 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/ | ||||||||||
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