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. > Intel introduces mechanism to detect split lock via alignment > check exception in Tremont and other future processors. If split lock is > from user process, #AC handler can kill the process or re-execute faulting > instruction depending on configuration. Ideally it would #AC any unaligned (implied) LOCK prefix instruction, not just across lines. > To detect split lock, a new control bit (bit 29) in per-core TEST_CTL > MSR 0x33 will be introduced in future x86 processors. When the bit 29 > is set, the processor causes #AC exception for split locked accesses at > all CPL. Per-Core is really unfortunate, but better than nothing.
