Re: [PATCH v3 10/11] perf tools report: Implement browsing of individual samples

From: Jiri Olsa
Date: Mon Mar 04 2019 - 09:48:00 EST

On Thu, Feb 28, 2019 at 10:35:49AM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Now report can show whole time periods with perf script,
> but the user still has to find individual samples of interest
> manually.
> It would be expensive and complicated to search for the
> right samples in the whole perf file. Typically users
> only need to look at a small number of samples for useful
> analysis.
> Also the full scripts tend to show samples of all CPUs and all
> threads mixed up, which can be very confusing on larger systems.
> Add a new --samples option to save a small random number of samples
> per hist entry
> Use a reservoir sample technique to select a representatve
> number of samples.
> Then allow browsing the samples using perf script
> as part of the hist entry context menu. This automatically
> adds the right filters, so only the thread or cpu of the sample
> is displayed. Then we use less' search functionality
> to directly jump the to the time stamp of the selected
> sample.

I'm getting this error for workload sampling:

File does not contain CPU events. Remove -C option to proceed.