On Sat, Mar 8, 2014 at 1:13 AM, Markus Trippelsdorf <mar...@trippelsdorf.de> wrote: > On 2014.03.08 at 08:51 +0100, Mike Galbraith wrote: >> On Fri, 2014-03-07 at 17:57 -0800, Andy Lutomirski wrote: >> > On recent (3.13) kernels, I'm frequently getting messages like: >> > >> > perf samples too long (2503 > 2500), lowering >> > kernel.perf_event_max_sample_rate to 50000 >> > >> > a few seconds to minutes after bootup. As far as I know, I'm not >> > using perf. What's going on here? >> >> 14c63f17b1 >> >> I get those all the time too, just building kernels. > > I have: > echo 0 > /proc/sys/kernel/perf_cpu_time_max_percent > in my local startup script since that commit.
...so the NMI watchdog (which happens IIRC once every two minutes) takes more than 0.4ms or so, so perf flips out, changes its parameters, and writes a log message. Is it just me or is this whole situation screwed up for multiple reasons? --Andy > > -- > Markus -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
