Messages in this thread | | | Date | Thu, 21 Jun 2018 22:32:57 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses |
| |
On Thu, 21 Jun 2018, Fenghua Yu wrote: > On Thu, Jun 21, 2018 at 09:37:38PM +0200, Peter Zijlstra wrote: > > On Sun, May 27, 2018 at 08:45:49AM -0700, Fenghua Yu wrote: > > > Currently we can trace split lock event counter for debug purpose. But > > > > How? A while ago I actually tried that, but I could not find a suitable > > perf event. > > The event name is called sq_misc.split_lock. It's been supported in perf > already.
So the obvious question is why not simply use that counter and capture the IP which triggers the event?
I can see that this wont cover the early boot process, but there it's enough to catch #AC once, yell loudly and then disable the thing. I'm not seing the value of adding 1000 lines of code with lots of control knobs.
I might be missing something though and am happy to be educated.
Thanks,
tglx
| |