Messages in this thread | | | Date | Thu, 14 Jul 2005 09:37:40 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt |
| |
On Thu, 14 Jul 2005, Vojtech Pavlik wrote: > > A note on the relaive timer API: There needs to be a way to say > "x milliseconds from the time this timer should have triggered" instead > of "x milliseconds from now", to avoid skew in timers that try to be > strictly periodic.
I disagree.
There should be an _absolute_ interface, and a driver that wants that should just have calculated when in time the timeout finishes - and then keep on using the absolute value.
Btw, this is exactly why the jiffy-based thing is _good_. The kernel timers _are_ absolute, and you make them relative by adding "jiffies".
The fact is, the current timers are better than people give them credit for, and converting them away from a jiffies-based interface (to a usleep-like one) is STUPID.
There's absolutely nothing wrong with "jiffies", and anybody who thinks that
msleep(20);
is fundamentally better than
timeout = jiffies + HZ/50;
just doesn't realize that the latter is a bit more complicated exactly because the latter is a hell of a lot more POWERFUL. Trying to get rid of jiffies for some religious reason is _stupid_.
I have to say, this whole thread has been pretty damn worthless in general in my not-so-humble opinion.
Linus - 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/
| |