Re: [patch V6 01/37] tracing/hwlat: Use ktime_get_mono_fast_ns()

[Thomas Gleixner]

Steven Rostedt <rostedt@xxxxxxxxxxx> writes:
> On Sat, 16 May 2020 01:45:48 +0200
> Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>> +	if (enter)
>> +		nmi_ts_start = ktime_get_mono_fast_ns();
>> +	else
>> +		nmi_total_ts += ktime_get_mono_fast_ns() - nmi_ts_start;
>>  
>>  	if (enter)
>>  		nmi_count++;
>> @@ -165,20 +155,22 @@ void trace_hwlat_callback(bool enter)
>>   * Used to repeatedly capture the CPU TSC (or similar), looking for potential
>>   * hardware-induced latency. Called with interrupts disabled and with
>>   * hwlat_data.lock held.
>> + *
>> + * Use ktime_get_mono_fast() here as well because it does not wait on the
>> + * timekeeping seqcount like ktime_get_mono().
>
> When doing a "git grep ktime_get_mono" I only find
> ktime_get_mono_fast_ns() (and this comment), so I don't know what to compare
> that to. Did you mean another function?

Yeah. I fatfingered the comment. The code uses ktime_get_mono_fast_ns().

> The rest looks fine (although, I see other things I need to clean up in
> this code ;-)

Quite some ...

Thanks,

        tglx