Re: [PATCH v3 0/4] Some new features for the latency tracers

[Steven Rostedt]

On Mon, 13 May 2019 23:50:04 +0200
Viktor Rosendahl <viktor.rosendahl@xxxxxxxxx> wrote:

> Hello all,

Hi Viktor,

Note, as the merge window is open and I'm also currently at a
conference, it may be a while before I can take a look at this. If you
don't hear something from me in 10 days, feel free to send me a ping.

-- Steve



> 
> Changes in v3:
> - [PATCH 1/4]: 
>   * I have generalized this to send the fsnotify() notifications for all
>     tracers that use tracing_max_latency.
> 
>   * There are large additions of code to prevent queue_work() from being
>     called while we are in __schedule() or do_idle(). This was a bug also
>     in the previous version but had gone unnoticed. It became very visible
>     when I tried to make it work with the wakeup tracers because they are
>     always invoked from the sched_switch tracepoint.
> 
>   * The fsnotify notification is issued for tracing_max_latency, not trace.
> 
>   * I got rid of the kernel config option. The facility is always compiled
>     when CONFIG_FSNOTIFY is enabled and any of the latency tracers are
>     enabled.
> 
> - [PATCH 2/4]:
>   * No significant changes.
> 
> - [PATCH 3/4]:
>   * The latency-collector help messages have been tuned to the fact that it
>     can be used also with wakeup and hwlat tracers.
> 
>   * I increased the size of the buffer for reading from
>     /sys/kernel/debug/tracing/trace.
> 
>   * Adapted it to monitor tracing_max_latency instead of trace
> 
> - [PATCH 4/4]:
>   * I converted this from a kernel config option to a trace config option
>     that can be changed at runtime.
> 
>