Messages in this thread Patch in this message | | | Subject | Re: ia64 cpu hotplug patch | From | Rusty Russell <> | Date | Wed, 19 May 2004 10:44:50 +1000 |
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On Wed, 2004-05-19 at 09:58, Ashok Raj wrote: > 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....
OK, well if you're correlating /proc/cpuinfo (online cpus) and /proc/stat (possible cpus), then I can understand top getting upset.
Perhaps we should only show online cpus in /proc/stat, but the totals displayed must still include all CPUs I think.
How's this version:
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. The totals printed by /proc/stat (the first loop) should include offline cpus, too (apparently printing out the per-cpu lines for offline cpus confuses top).
diff -Nru a/fs/buffer.c b/fs/buffer.c --- b/fs/buffer.c Fri May 14 19:00:11 2004 +++ a/fs/buffer.c Thu Apr 22 16:20:51 2004 @@ -3019,7 +2966,7 @@ if (__get_cpu_var(bh_accounting).ratelimit++ < 4096) return; __get_cpu_var(bh_accounting).ratelimit = 0; - for_each_online_cpu(i) + for_each_cpu(i) tot += per_cpu(bh_accounting, i).nr; buffer_heads_over_limit = (tot > max_buffer_heads); } diff -Nru a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c --- 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;
-- Anyone who quotes me in their signature is an idiot -- Rusty Russell
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