Hi Stephane, On Oct 23, 2009, at 2:18 PM, stephane eranian wrote:
> Ken, > > On Fri, Oct 23, 2009 at 1:41 PM, Kenneth Hoste > <kenneth.ho...@ugent.be> wrote: >> >> The Intel documentation for Core i7 suggests that this is not the >> case >> on Nehalem, i.e. uops fused through micro-fusion are counted as 2 >> uops >> (while macro-fused uops are counted as 1), like you mentioned above. >> >> We missed this point somehow in your first reply, sorry about that. >> >> Thus, in order to obtain sensible numbers, it does indeed seem that >> we need to figure out the number of micro-fused uops in Core i7, and >> subtract that from the UOPS_RETIRED.ANY count we have now... >> >> It seems like there is no event for directly counting retied micro- >> fused >> uops >> however (while there is for UOPS_RETIRED.MACRO_FUSED). >> > >> Are we missing something? Should we be able to get counts for retired >> micro-fused uops? If so, which event are you referring to? If not, >> any ideas >> on how we can obtain uops_retired counts on Core i7 where micro-fused >> uops are counted as 1? >> > It does not seem possible because you have 2 unknowns in the equation: > > uops_retired.any = uops_retired.normal + uops_retired.micro + > 2*uops_retired.micro. > > You are missing micro and normal. > I thought you could may be do it by comparing what goes in with what > comes out, > but that would only give you the wasted uops (on the wrong > speculative path). > > I will on that some more. > There are some information of interest in the Intel Optimization guide > (Appendix B2). > > http://www.intel.com/Assets/PDF/manual/248966.pdf We ended up using a pragmatic approach in order to obtaini sensible retired uop counts on Core i7, which are comparable to Core2 retired uop counts. As stated above, the problem is that micro-fused uops are counted as 2 in the UOPS_RETIRED.ANY event (as opposed to the Core 2 event), and that there is no way to obtain the retired micro-fused uops count separately. We ended up by estimating the amount of micro-fused uops by counting the number of issues uops, using UOPS_ISSUED.ANY and UOPS_ISSUED.FUSED. We figured out that the UOPS_ISSUED.FUSED only counts micro-fused uops as one. That way, we can estimate the amount of micro-ops in UOPS_RETIRED.ANY by using the UOPS_ISSUED.FUSED / UOPS_ISSUED.ANY ratio, and thus correct the UOPS_RETIRED.ANY accordingly. In short, we can use the following as an estimate for retired uops where each type of uop (non-fused, macro-fused, micro-fused) is counted as one: UOPS_RETIRED.ANY * (1 - UOPS_ISSUED.FUSED / UOPS_ISSUED.ANY) I hope that makes sense.... greetings, Kenneth ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
