On Wed, Jun 28, 2017 at 10:19 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote: > It seems odd that an event without any samples to take has a sample > period. I'm surprised that there's not *some* sample_type set. Yes, it is a bit odd :-). Rather than trying to gather some limited set of information about the target process, we want to interrupt its execution after a particular number of events have occurred. The bigger picture here is that we're replaying a previously recorded process execution. We want to the process to run until it reaches a particular state that occurred during recording; that state is identified by a value for the performance counter (retired conditional branches) plus the values of the general-purpose registers. So our first step is to run the process until the performance counter reaches a value less than but "close to" the target value. (We know the process will be interrupted after a number of extra events have occurred, so we set the sample period to a value less than the target by a heuristic "maximum skid size".) Rob -- lbir ye,ea yer.tnietoehr rdn rdsme,anea lurpr edna e hnysnenh hhe uresyf toD selthor stor edna siewaoeodm or v sstvr esBa kbvted,t rdsme,aoreseoouoto o l euetiuruewFa kbn e hnystoivateweh uresyf tulsa rehr rdm or rnea lurpr .a war hsrer holsa rodvted,t nenh hneireseoouot.tniesiewaoeivatewt sstvr esn