Hi Vince, On 10/19/2016 05:10 PM, Vince Weaver wrote: > > Linux 4.3 (71ef3c6b9d4665ee7afbbe4c208a98917dcfc32f) > added a cycles field to the PERF_SAMPLE_BRANCH_STACK > last branch records. > > The kernel commit was a bit vague on this, but you can find > a few more details on this in the Intel Architectural Manual > vol3B. The field indicates the number of core cycles elapsed > since the previous update to the LBR stack. > > This feature is only found on Skylake and newer Intel chips, > as well as Intel Atom Goldmont chips. I'm not sure if it's > worth adding this info to the manpage, as it seems a bit > specific and will probably get rapidly out of date. > > I'm also not sure about the manpage project's opinion on > Oxford commas. We like them! Patch applied. One comment below. > > Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx> > > diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 > index d64adaf..c9555c6 100644 > --- a/man2/perf_event_open.2 > +++ b/man2/perf_event_open.2 > @@ -2183,15 +2183,18 @@ The branch was in a transactional memory transaction. > .IR abort " (since Linux 3.11)" > .\" commit 135c5612c460f89657c4698fe2ea753f6f667963 > The branch was in an aborted transactional memory transaction. > +.TP > +.IR cycles " (since Linux 4.3)" > +.\" commit 71ef3c6b9d4665ee7afbbe4c208a98917dcfc32f > +This reports the number of cycles elapsed since the > +previous branch stack update. > .P > The entries are from most to least recent, so the first entry > has the most recent branch. > > Support for > -.I mispred > -and > -.I predicted > -is optional; if not supported, both > +.IR mispred ", " predicted " and " cycles Rather than the previous, I mostly prefer something like: Support for .IR mispred , .IR predicted , and .IR cycles I actually find source in that format a little easier to read, and a lot easier to script against. Cheers, Michael > +is optional; if not supported, those > values will be 0. > > The type of branches recorded is specified by the > -- > To unsubscribe from this list: send the line "unsubscribe linux-man" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
