Messages in this thread | | | From | Denis Vlasenko <> | Subject | Re: [RFC][PATCH] iowait statistics | Date | Wed, 15 May 2002 15:02:57 -0200 |
| |
On 14 May 2002 00:18, Andrew Morton wrote: > Rik van Riel wrote: > > 4) on SMP systems the iowait time can be overestimated, no big > > deal IMHO but cheap suggestions for improvement are welcome > > I suspect that a number of these statistical accounting mechanisms > are going to break. The new irq-affinity code works awfully well. > > The kernel profiler in 2.5 doesn't work very well at present. > When investigating this, I ran a busy-wait process. It attached > itself to CPU #3 and that CPU received precisely zero interrupts > across a five minute period. So the profiler cunningly avoids profiling > busy CPUs, which is rather counter-productive. Fortunate that oprofile > uses NMI.
What, even local APIC interrupts did not happen on CPU#3 in these five mins? -- vda - 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/
| |