On Sat, Apr 14, 2007 at 12:30:17AM +0200, Ingo Molnar wrote: > > * Daniel Walker <[EMAIL PROTECTED]> wrote: > > > I'm not in love with the current or other schedulers, so I'm > > indifferent to this change. However, I was reviewing your release > > notes and the patch and found myself wonder what the logarithmic > > complexity of this new scheduler is .. I assumed it would also be > > constant time , but the __enqueue_task_fair doesn't appear to be > > constant time (rbtree insert complexity).. [...] > > i've been worried about that myself and i've done extensive measurements > before choosing this implementation. The rbtree turned out to be a quite > compact data structure: we get it quite cheaply as part of the task > structure cachemisses - which have to be touched anyway. For 1000 tasks > it's a loop of ~10 - that's still very fast and bound in practice.
I'm not worried at all by O(log(n)) algorithms, and generally prefer smart log(n) than dumb O(1). In a userland TCP stack I started to write 2 years ago, I used a comparable scheduler and could reach a sustained rate of 145000 connections/s at 4 millions of concurrent connections. And yes, each time a packet was sent or received, a task was queued/dequeued (so about 450k/s with 4 million tasks, on an athlon 1.5 GHz). So that seems much higher than what we currently need. Regards, Willy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
