Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [patch V5 04/38] x86: Make hardware latency tracing explicit | Date | Fri, 15 May 2020 17:08:56 +0200 |
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Steven Rostedt <rostedt@goodmis.org> writes:
> On Tue, 12 May 2020 23:01:03 +0200 > Thomas Gleixner <tglx@linutronix.de> wrote: > >> --- a/arch/x86/kernel/cpu/mce/core.c >> +++ b/arch/x86/kernel/cpu/mce/core.c >> @@ -1916,7 +1916,7 @@ static __always_inline void exc_machine_ >> mce_check_crashing_cpu()) >> return; >> >> - nmi_enter(); >> + nmi_enter_notrace(); > > Now a machine check exception could happen and be a cause of latency > (although there may be more issues if it does). The "nmi_enter trace" > version does two things. One is for time measurements (if available), > and the other is just letting the hardware latency know it happen (a > simple increment). > > The only thing that is checked is "smp_processor_id()" (I just > remembered it doesn't need per cpu, as it only runs on a single CPU at > a time). > > Could the notrace version supply the increment, and leave the > trace_clock() in the trace version?
Yes, I can split it up that way.
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