On 08/07/15 16:28, Arnaldo Carvalho de Melo wrote: > Em Wed, Jul 08, 2015 at 12:52:40AM +0200, Peter Zijlstra escreveu: >> On Tue, Jul 07, 2015 at 01:13:59PM -0300, Arnaldo Carvalho de Melo wrote: >>> Em Tue, Jul 07, 2015 at 05:36:14PM +0200, Peter Zijlstra escreveu: >>>>> To help userspace in places where all it has is the union perf_event, we >>>>> can reuse one bit in misc to state that, i.e. > >>>>> #define PERF_RECORD_MISC_SWITCH_NEXT_PREV_PID 14 > >>>>> For instance. > >>>> The other option would be a separate RECORD type, which might be >>>> simpler. > >>> Humm, do we really need it? > >>> I think this is just us wanting to, since we are going to add a new >>> record, to make it more useful for other, not right now needed, >>> situations, i.e. if the user is priviledged, there are two other options >>> to get his info, right? > >> I was just thinking that 2 records, each with a fixed layout would be >> easier to parse than 1 record with variable layout. > >> The record space is immense, so from that point it really doesn't >> matter. > > We could do a land grab at some point there, if/when we find some reason > for that... :-) > >> Do whatever is easiest, less mistakes get made etc. :-) > >> No real preference either way, as long we we've thought about it. > > Right, I just don't want to have two u32 carrying -1 for no reason.
So you'd be OK with 2 RECORD types? I will see what is involved. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/