On Thu, 25 Sep 2014 13:45:05 +0100, Pawel Moll wrote: > On Wed, 2014-09-24 at 07:07 +0100, Namhyung Kim wrote: >> On Tue, 23 Sep 2014 18:03:07 +0100, Pawel Moll wrote: >> > This patch adds a new PERF_COUNT_SW_UEVENT software event >> > and a related PERF_SAMPLE_UEVENT sample. User can now >> > write to the the perf file descriptor, injecting such >> > event in the perf buffer. >> >> It seems the PERF_SAMPLE_UEVENT sample can be injected to any event. So >> why the PERF_COUNT_SW_UEVENT is needed? At least one can use the >> SW_DUMMY event for that purpose. > > You're right. I needed a different SW type in one of my early > prototypes, but it's not the case any more. Consider it gone. Okay. > >> Also I think it'd be better to be a record type (PERF_RECORD_XXX) >> instead of a sample flag (PERF_SAMPLE_XXX). In perf tools, we already >> use perf_user_event_type for synthesized userspace events. This way it >> can avoid unnecessary sample processing for userspace events. > > Fine with me. If no one objects, I'm more than happy to use > PERF_RECORD_UEVENT = 11 for it. > >> For contents, I prefer to give complete control to users - kernel >> doesn't need to care about it other than its size. If one just wants to >> use strings only, she can write them directly. If others want to mix >> different types of data, they might need to define a data format for >> their use. > > Are you saying to drop even the "type 0 means zero-terminated string" > definition, even if everything else is up to the user? I quite like that > idea, especially combined with write()ing to the perf_fd (it is very > much like trace_marker then, which is beautiful in its simplicity), but > the feelings are not that strong to fight a war over it. :) Thanks, Namhyung -- 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
