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. > 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. Pawel -- 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
