Messages in this thread Patch in this message | | | Date | Tue, 18 May 2004 16:58:04 -0700 | From | Ashok Raj <> | Subject | Re: ia64 cpu hotplug patch |
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On Tue, May 18, 2004 at 04:45:56PM -0700, Rusty Russell wrote: > > On Wed, 2004-05-19 at 04:12, Anton Blanchard wrote: > > > Gack, Rusty, I wish you had less SMTP latency. I'm not sure what > > > this is about. If it pertains to some patch which I'm carrying, > someone > > > tell me what one ;) > > > > One of the ia64 hotplug patches that got merged. It seems they got > itchy > > fingers and changed a few more things than they should have. > > Precisely. This applies against Linus' kernel: > > Name: Fix overzealous use of online cpu iterators > Status: Trivial > > The IA64 hotplug CPU merge seems to have included some core changes: > in > particular the recalc_bh_state() needs to sum for all (including > offline) cpus, since we don't empty the counters on CPU down. I don't > know that anyone cares about the accuracy of the /proc/stat when CPUs > go > down, but certainly the totals printed (the first loop) should include > offline cpus.
Sorry... my mistake!
proc_misc.c was changed, since top() uses this to read and display stats. With cpuhotplug cpu_possible() represents the entire set of NR_CPUS, all these stats with 0 values and top gets all dorky about it.
Maybe the right thing would be to fix the utility instead ?
Other issue i noticied was that when we have a 4 cpu system, and you remove an intermediate cpu say cpu2, top utility is dorky again. And prints "invalid data" in the middle of the output.
Without the fix to proc_misc, if NR_CPUS is set to 128, top lists all 128 cpu stats even if only 4 are present and online, since for_each_cpu reprensents all of it....
> > --- b/fs/proc/proc_misc.c Fri May 14 23:11:58 2004 > +++ a/fs/proc/proc_misc.c Tue Mar 23 02:05:27 2004 > @@ -368,7 +368,7 @@ > if (wall_to_monotonic.tv_nsec) > --jif; > > - for_each_online_cpu(i) { > + for_each_cpu(i) { > int j; > > user += kstat_cpu(i).cpustat.user; > @@ -390,7 +390,7 @@ > (unsigned long long)jiffies_64_to_clock_t(iowait), > (unsigned long long)jiffies_64_to_clock_t(irq), > (unsigned long long)jiffies_64_to_clock_t(softirq)); > - for_each_online_cpu(i) { > + for_each_cpu(i) { > > /* Copy values here to work around gcc-2.95.3, > gcc-2.96 */ > user = kstat_cpu(i).cpustat.user; > > -- > Anyone who quotes me in their signature is an idiot -- Rusty Russell > > - > 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 [1]http://vger.kernel.org/majordomo-info.html > Please read the FAQ at [2]http://www.tux.org/lkml/ > > References > > 1. http://vger.kernel.org/majordomo-info.html > 2. http://www.tux.org/lkml/ - 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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