Messages in this thread | | | Date | 27 Apr 2007 11:09:17 +0200 | Date | Fri, 27 Apr 2007 11:09:17 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH] x86_64: dynamic MCE poll interval |
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On Thu, Apr 26, 2007 at 06:02:52PM -0700, Tim Hockin wrote: > Description: > This patch makes the MCE poller adjust the polling interval dynamically. > If we find an MCE, poll 2x faster (down to 10 ms). When we stop finding > MCEs, poll 2x slower (up to check_interval seconds). The check_interval > tunable becomes the max polling interval.
Can you please fix the documentation then?
> > Result: > If you start to take a lot of correctable errors (not exceptions), you > log them faster and more accurately (less chance of overflowing the MCA > registers). If you don't take a lot of errors, you will see no change.
Makes sense.
AMD RevF can do this using the threshold interrupts too for DIMM errors too without any delays -- perhaps it would also make sense to configure this by default that it always triggers on all DIMM errors. Right now it is just an option in /sys
> @@ -349,17 +349,24 @@ static void mcheck_timer(struct work_str > * writes. > */ > if (notify_user && console_logged) { > + /* if we logged an MCE, reduce the polling interval */ > + next_interval = max(next_interval/2, HZ/100); > notify_user = 0; > clear_bit(0, &console_logged); > printk(KERN_INFO "Machine check events logged\n");
The printk should not happen too often. Can you add some hardcoded limit there than it doesn't happen more often than every hour or so (or perhaps use a exponential backoff here too?) It is only to tell users to check mcelog output.
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