Re: [PATCH] x86_64: dynamic MCE poll interval

From: Tim Hockin
Date: Fri Apr 27 2007 - 12:58:59 EST

On 27 Apr 2007 11:09:17 +0200, Andi Kleen <ak@xxxxxx> wrote:
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?

Which documentation, specifically? :)

> 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

Can I look at this as a followon patch? I have a number of mce
related patches in the pipeline, and I am trying to keep them small
for testing sanity - they are hard enough to test :)

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.

Sure. I'll fix it up and hit you again today.
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