summaryrefslogtreecommitdiffstats
path: root/kernel/events
diff options
context:
space:
mode:
authorDave Hansen <dave.hansen@linux.intel.com>2013-06-21 17:51:35 +0200
committerIngo Molnar <mingo@kernel.org>2013-06-23 11:52:56 +0200
commit2ab00456ea8a0d79acb1390659b98416111880b2 (patch)
tree5bda8b0f3f8a530431691e5ab309b6f2f056894e /kernel/events
parenthw_breakpoint: Introduce "struct bp_cpuinfo" (diff)
downloadlinux-2ab00456ea8a0d79acb1390659b98416111880b2.tar.xz
linux-2ab00456ea8a0d79acb1390659b98416111880b2.zip
x86: Warn when NMI handlers take large amounts of time
I have a system which is causing all kinds of problems. It has 8 NUMA nodes, and lots of cores that can fight over cachelines. If things are not working _perfectly_, then NMIs can take longer than expected. If we get too many of them backed up to each other, we can easily end up in a situation where we are doing nothing *but* running NMIs. The biggest problem, though, is that this happens _silently_. You might be lucky to get an hrtimer warning, but most of the time system simply hangs. This patch should at least give us some warning before we fall off the cliff. the warnings look like this: nmi_handle: perf_event_nmi_handler() took: 26095071 ns The message is triggered whenever we notice the longest NMI we've seen to date. You can always view and reset this value via the debugfs interface if you like. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: paulus@samba.org Cc: acme@ghostprotocols.net Cc: Dave Hansen <dave@sr71.net> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
0 files changed, 0 insertions, 0 deletions