Messages in this thread | | | Date | Mon, 13 Dec 2004 19:56:55 -0800 | From | Nish Aravamudan <> | Subject | Re: dynamic-hz |
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On Mon, 13 Dec 2004 12:47:37 +0100, Andrea Arcangeli <andrea@suse.de> wrote: > On Mon, Dec 13, 2004 at 03:25:21AM -0800, Andrew Morton wrote: > > We still have 1000-odd places which do things like > > > > schedule_timeout(HZ/10); > > > > which will now involve a runtime divide. The propagation of msleep() and > > ssleep() will reduce that a bit, but not much. > > The above is by far the least cpu-hungry piece, it's going to sleep for > 100msec, so any order-of-nanoseconds computation in such path will be by > defininition not measurable. > > msleep and ssleep as well will obviously be non measurable for the same > reason (their only point is to wait and "waste" cpu). I mean, > msleep/ssleep are the only places in the kernel that we don't really > need to optimize ;).
I don't exactly understand what you mean by ""waste" cpu"? They both give up the CPU by calling schedule_timeout() which calls schedule(). So any "waste" of the CPU is due to no tasks being available to run, not to msleep()/ssleep(). I think :)
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