Messages in this thread | | | Date | Fri, 18 Oct 2002 12:51:37 +0100 | From | Neil Conway <> | Subject | Re: [PATCH] 2.4: variable HZ |
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Hiya... Nice patch, must try it when I find a few minutes - I think I have a few apps that are limited by select/poll behaviour.
I was looking at your jiffies_to_clock_t() macro, and I notice that it will screw up badly if the user chooses a HZ value that isn't a multiple of the normal value (e.g. 1000 is OK, 512 isn't).
How about tweaking the macro a little? Instead of: x / (HZ/USER_HZ) you could use: (x/HZ*USER_HZ + x%HZ*USER_HZ/HZ)
which minimises roundoff error and also won't overflow (at least, it won't overflow as long as HZ*USER_HZ doesn't overflow!).
You could even use both versions of the macro, choosing between them at compile time depending on whether or not (HZ % USER_HZ == 0).
What do you think?
cheers Neil PS: I'm off-list. - 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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