>>>>> "LT" == Linus Torvalds <[EMAIL PROTECTED]> writes:
LT> On Wed, 3 Oct 2007, Chuck Ebbert wrote: >> >> But we reduce the number of samples because some ticks just never >> happen when the timers get rounded: >> >> No rounding: >> >> tick ............... tick >> 1 running 1 running >> >> Rounded: >> >> tick >> 2 running >> >> In the first case the average is 1, but it's 2 in the second. LT> In fact, I think this is it! LT> The load average is not calculated every tick, because that's not just LT> expensive, but we also want to have some time-based decay. So it's LT> calculated every LOAD_FREQ ticks. LT> And guess what: LOAD_FREQ is defined to be exactly five seconds. LT> So imagine if the timer gets to be in sync with another event that happens LT> every five seconds - let's pick at random a 5-second JBD transaction LT> thing? LT> Anders - does this idiotic patch make a difference for you? Yes, it does, it fixes the load average!!! I guess we have something here! Why does this problem only show up on my computer? Any idea? / Anders LT> Without this, I can easily imagine that the rounding code tends to try to LT> round to an even second, and the load-average code generally also runs at LT> even seconds! LT> Linus LT> --- LT> include/linux/sched.h | 2 +- LT> 1 files changed, 1 insertions(+), 1 deletions(-) LT> diff --git a/include/linux/sched.h b/include/linux/sched.h LT> index a01ac6d..643de0f 100644 LT> --- a/include/linux/sched.h LT> +++ b/include/linux/sched.h LT> @@ -113,7 +113,7 @@ extern unsigned long avenrun[]; /* Load averages */ LT> #define FSHIFT 11 /* nr of bits of precision */ LT> #define FIXED_1 (1<<FSHIFT) /* 1.0 as fixed-point */ LT> -#define LOAD_FREQ (5*HZ) /* 5 sec intervals */ LT> +#define LOAD_FREQ (5*HZ+1) /* ~5 sec intervals */ LT> #define EXP_1 1884 /* 1/exp(5sec/1min) as fixed-point */ LT> #define EXP_5 2014 /* 1/exp(5sec/5min) */ LT> #define EXP_15 2037 /* 1/exp(5sec/15min) */ - 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/
