Re: [PATCH 0/2] perf: User/kernel time correlation and event generation

[Christopher Covington <cov@codeaurora.org>]

Hi Pawel,

On 09/18/2014 10:34 AM, Pawel Moll wrote:
> Greetings,
> 
> This is a second spin of the short series posted last week:
> 
> http://www.spinics.net/lists/kernel/msg1824419.html
> 
> The first patch adds an additional timestamp field in the perf
> sample data, which can be requested for any perf event along
> with normal PERF_SAMPLE_TIME. Events with both values appearing
> periodically in the perf data allow user code to translate
> raw monotonic time (obtained via POSIX clock API) to sched_clock
> domain. Although any perf event can be used, the natural choice
> would be a sched_switch trace event (for processes with root
> permissions) or a hrtimer-based PERF_COUNT_SW_CPU_CLOCK.
> 
> It didn't attract any comments previously, so is just re-posted
> without any changes.
> 
> The second patch, functionally orthogonal but complementing
> the first one, builds on the ftrace "trace_maker" idea. It adds
> a ioctl that can be used to inject a userspace-generated data
> into the perf buffer. It provides base for printf-like
> functionality in perf world. If used with the previous patch,
> it can be also used to provide synchronisation points for sched
> vs. raw monotonic time stamps correlation.
> 
> First version of the patch was taking a zero-terminated string
> as an argument. Now it is taking a custom structure with "type"
> and "size" integer fields followed by data. Type value "0"
> is defined as a zero-terminated string (although size, including
> the NULL character, must still be provided), but meaning of data
> for other types is of no interest for the kernel. The intention
> is to host a list of "well known" types (with reference parsers
> for them) in the user perf tool code.

Would it be possible for you to also update the corresponding man pages?

https://www.kernel.org/doc/man-pages/

Thanks,
Christopher

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