Messages in this thread |  | | Date | Sun, 10 Jan 1999 01:25:50 +0100 | | From | Horvath Karoly <> | | Subject | Re: [PATCH] HZ change for ix86 |
| |
On Sat, Jan 09, 1999 at 07:05:16PM -0500, Richard B. Johnson wrote: > > > There seems to be a general misinformation about what the HZ value is. > > > I will "simplicate and add lightness". > > > > still darkness here.... > > > > > However, if your code is doing: > > > > > > UncompressFonts(...........); > > > ReadAudioFromDsp(...........); > > > ConvolveImageData(..........); > > > > > > you don't want the CPU taken away until you are done. > > > > We can't prevent the kernel from taking away the CPU - and a higher HZ value > > helps us get back the CPU as soon as possible. > > If we don't do blocking system calls, we don't lose the CPU until our > time-slice is up. > > Once you lose the CPU, you may lose it for N time slices because there > are N computable tasks that will get it before you get it back. This is a > multitasking operating system with many more tasks than just yours. You > get it CPU back when it's your turn, not the next timer-tick. > > If N tasks are CPU bound, you sure want a long time-slice before the > CPU gets stolen from you.
Why? Each of the N processes gets the 1/N of the CPU - wheter there are long or short timeslices. If you have the CPU for long time, you'll miss it for long time...
> > > doesn't produce visual effects. The higher the HZ value, the more > > > often the CPU gets stolen from the interactive user. > > > > Why is that a problem? Here is an example: > > You earn 1000$ a month. Your boss decides to pay you not monthly but weekly, > > and you begin to complain that you earn only 250$. > > Not accurate.
I think so.
Anybody, who agrees with Johnson?
-- [:)]--------------------------- [:)] Horvath Karoly Zoltan / Technical University of Budapest [:)] rh@the.rulez.org / an active member of AC Studio & Live [:)]-------------------------
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
|  |