Hi Mathieu, This feature seems not to have made it into 4.9. (Or did I miss something?) Is it still planned for a future release? Cheers, Michael On 08/12/2016 07:56 PM, Mathieu Poirier wrote: > On 12 August 2016 at 10:52, Vince Weaver <vince@xxxxxxxxxx> wrote: >> On Thu, 11 Aug 2016, Mathieu Poirier wrote: >> >>> This manpage patch relates to the addition of the >>> PERF_EVENT_IOC_SET_DRV_CONFIGS ioctl. >>> >>> link: http://www.spinics.net/lists/kernel/msg2318998.html >>> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> >>> --- >>> man2/perf_event_open.2 | 6 ++++++ >>> 1 file changed, 6 insertions(+) >>> >>> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 >>> index 3c894ccd1209..315b6a91079a 100644 >>> --- a/man2/perf_event_open.2 >>> +++ b/man2/perf_event_open.2 >>> @@ -2732,6 +2732,12 @@ The argument is a BPF program file descriptor that was created by >>> a previous >>> .BR bpf (2) >>> system call. >>> +.TP >>> +.BR PERF_EVENT_IOC_SET_DRV_CONFIGS " (since Linux 4.9)" >>> +This makes it possible to pass configuration parameters to PMU drivers. >>> +Configuration parameters are specific to each drivers. >>> + >>> +The argument is a pointer to the desired configuration parameters. >>> .SS Using prctl >>> A process can enable or disable all the event groups that are >>> attached to it using the >> >> This is a bit... vague. So we're adding an interface to allow passing >> arbitrary binary blobs through the perf_event interface? >> >> Is there any structure at all to these blobs? From the other commit >> messages it looked like you'd be passing in some sort of string. > > I am adding an interface to pass PMU specific configuration to the > driver. Since PMU drivers exist for different architecture and > drivers I am making the mechanism as generic as possible. > > In this case the CoreSight Tracers need to know what "sink" to use for > a trace session. I've enhanced the perf cmd line tool to accept: > > perf -e cs_etm/@sink=some_sink_definition/ .... > > Everything falling with the '/' that is preceded by a '@' character is > considered PMU driver material. At this time the perf lexer accept > two format: > > "@cfg" and "@cfg=option". The lexer will strip off the '@' and pass > "cfg" and "cfg=option" to the kernel. > > What gets sent down to the kernel is driver specific - it is up to the > PMU drivers to parse and validate what's given to them. > > This feature loosely mimics the filter enhancement where it is now > possible to specify: > > perf record -e some_event// --filter 'start 0xstart_addr,stop 0xstop_address' or > perf record -e some_event// --filter 'filter 0xstart_address/offset' > > Here it is up to the event to supply the mechanic to deal with the > filter specification (I'm doing the same thing). Keywords "start", > "stop" and "filter" are common to both IntelPT and CoreSight tracers, > making them ideal candidates for parsing in the core. > > But for driver specific configuration "sink" is only applicable to > CoreSight tracers... > > Writing these lines I realise that "start", "stop" and "filter" are > applicable to only two drivers (IntelPT and CoreSight). Peter, do you > think I should look for "sink" in the core parser, just like it is > done for filters? > > Guidance would be appreciated here. > > Mathieu > >> >> Vince > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
