Re: Sample memory references with at least a given latency?

[Harald Servat <harald.servat@bsc.es>]

Hello Manuel,

   I'm running Linux 3.11 but I don't see a way to setup the latency 
threshold there. My option flags include:

        -t, --type=
        -D, --dump-raw-samples=
        -x, --field-separator
        -C, --cpu-list

   so I guess that this option is not implemented in perf (at least on 
3.11). So I need to capture all the samples and then discard those that 
surpass that threshold.

   Going back into your example, is it possible to capture / show the 
timestamp for the captured samples? I've seen the Intel documentation, 
and there aren't timestamps in PEBS entries so that may require 
additional work. IIRC, someone of the list told me that perf allocates a 
1-entry PEBS buffer so every time PEBS fills it, perf somehow gets an 
interrupt indicating that it has to flush it. This way, perf can 
attribute a timestamp to that sample also.

Thank you very much!


On 04/02/15 15:00, Manuel Selva wrote:
> Hi Harald,
>
> Yes you can with the "perf mem" tool. It has been introduced in kernel
> 3.10 (correct me if I am wrong, not very sure about that). It's built on
> top of perf mem record and perf mem report but hide for you the
> complxity of choosing the memory events . See "man perf mem" for th details.
>
> ----------
> Manuel
>
>
>
> 2015-02-04 13:48 GMT+01:00 Harald Servat <harald.servat@bsc.es
> <mailto:harald.servat@bsc.es>>:
>
>     Hello list,
>
>        is there any way to configure perf to sample memory references
>     through PEBS and enable the Load Latency Performance Monitoring
>     Facility (section 18.7.1.2 from the Intel 64 and IA-32 Architectures
>     Software Developer's Manual).
>
>     Thank you very much in advance.
>
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