[PATCH] /proc/uptime on SMP machines

Uwe Bonnes (bon@elektron.ikp.physik.tu-darmstadt.de)
Sun, 18 Mar 2001 00:30:36 +0100


Hallo,

I didn't see a maintainer for the /proc filesystem, to I send this mail to
linux-kernel for discussion.

At present the idle value in /proc/uptime is only the idle time for the first
processor. With 2.4, processes seam "stickier" for my, and e.g "yes
>/dev/null" on an otherwise idle machine can stay for a long time on one
processor of my (intel) SMP machine. That way, the present output of
/proc/uptime can lead to a wrong conclusion.

Appended patch returns the average of all idle processes an all
processors.

If I don't hear back, I will send to Linus and Alan for inclusion.

Bye

Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de

Free Software: If you contribute nothing, expect nothing

--

--- linux-2.4.2.SuSE/fs/proc/proc_misc.c Thu Mar 15 16:48:04 2001 +++ linux-2.4.2.SuSE-5/fs/proc/proc_misc.c Sat Mar 17 23:11:47 2001 @@ -105,11 +105,15 @@ { unsigned long uptime; unsigned long idle; - int len; + int len,i; uptime = jiffies; +#ifdef CONFIG_SMP + for (idle =0,i = 0; i < smp_num_cpus; i++) + idle += (init_tasks[i]->times.tms_utime + init_tasks[i]->times.tms_stime)/smp_num_cpus; +#else idle = init_tasks[0]->times.tms_utime + init_tasks[0]->times.tms_stime; - +#endif /* The formula for the fraction parts really is ((t * 100) / HZ) % 100, but that would overflow about every five days at HZ == 100. Therefore the identity a = (a / b) * b + a % b is used so that it is - 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/