Messages in this thread | | | Date | Mon, 28 May 2012 21:21:57 +0200 | From | Jiri Olsa <> | Subject | Re: [RFCv2 0/8] perf tool: Add new event group management |
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On Sun, May 27, 2012 at 03:56:22AM -0400, Ulrich Drepper wrote: > On Sat, May 26, 2012 at 8:38 AM, Jiri Olsa <jolsa@redhat.com> wrote: > > If you have some ideas on this or real world examples, > > that would really help.. so far, here's the latest discussion: > > http://marc.info/?t=133357436900005&r=1&w=2 > > If you're looking for a definitive source, just point to the Intel > optimization manual. Absolute values of counters are not really > useful and so they are defining many (50+) ratios which people should > investigate. These ratios are only really accurate if the counters > are swapped in and out at the same time.
thanks a lot for the pointer, very useful
> > The reminds me of a detail I looked at when starting an an > implementation for this (glad you got more time to devote to it). The > problem with ratios are that there are so many. So efficient > scheduling is going to be important. Many ratios use as a base the > same counters over and over again (e.g., cycle count, instruction > count, etc). Therefore it is important to recognize when two groups > can be scheduled concurrently even if the total number of counters > needed would be high but due to intersections it is possible. > > One last comment, not critical. From a parsing point of view the > colon in the proposed syntax > > name : { counter1, counter2 } > > is unnecessary. Just one more thing people can get wrong. How about > leaving it out? An open curly brace to indicate a group should be > sufficient.
yep, we'll omit the first colon
I'll CC you guys on next patchset
thanks, jirka
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