On Wed, Apr 07, 2021 at 04:28:40PM +0300, Adrian Hunter wrote: > On 7/04/21 4:15 pm, Leo Yan wrote: > > Hi Al, > > > > On Tue, Apr 06, 2021 at 09:38:32AM +0000, Al Grant wrote: > > > > [...] > > > >>> This patch set is to enable timestamp for Arm SPE trace. It reads out TSC > >>> parameters from mmap page and stores into auxtrace info structure; > >> > >> Why not synthesize a PERF_RECORD_TIME_CONV - isn't that specifically to > >> capture the TSC parameters from the mmap page? If a generic mechanism > >> exists it would be better to use it, otherwise we'll have to do this again > >> for > >> future trace formats. > > > > Good point! Actually "perf record" tool has synthesized event > > PERF_RECORD_TIME_CONV. This patch series is studying the > > implementation from Intel-PT, so the question is why the existed > > implementations (like Intel-PT, Intel-BTS) don't directly use > > PERF_RECORD_TIME_CONV for retriving TSC parameters. > > PERF_RECORD_TIME_CONV was added later because the TSC information is > needed by jitdump.
Thanks for the info, Adrian. If so, it's good for Arm SPE to use PERF_RECORD_TIME_CONV for TSC parameters. Will spin patch series for this. Leo
