On Thu, Feb 02, 2012 at 12:02:27PM -0800, Junio C Hamano wrote: > > Thanks for a patch. How does this compare with what was discussed in the > other thread? > > http://thread.gmane.org/gmane.comp.version-control.git/188992/focus=189172 I wasn't aware of this other approach when I created this patch (I must have missed the e-mail thread, sorry). One of the reasons why I did it this way was for more flexibility. I wanted to be able to do: $ make PROFILE_GEN=YesPlease PROFILE_DIR=/var/cache/FDO all # make PROFILE_GEN=YesPlease PROFILE_DIR=/var/cache/FDO install run a bunch of git commands on various git repositories to get real-life usage... Then do... $ make PROFILE_USE=YesPlease PROFILE_DIR=/var/cache/FDO all # make PROFILE_GEN=YesPlease PROFILE_DIR=/var/cache/FDO install But for many people they would probably be satisfied with something that builds git using a single magic recipe, even if they give up some fractional performance improvement (keep in mind that the feedback directed optimization seems to buy you only a single digit percentage improvement according according to Andi's original experiment; I just got interested in this more for amusement value than any thought that it would save me serious amounts of time). > I would wish a solution ideally would support > > make PROFILE_BUILD=YesPlease > make PROFILE_BUILD=YesPlease install At least in theory, it should be possible to have something which supports both PROFILE_GEN/PROFILE_USE as well as a combined PROFILE_BUILD. The hard part is that PROFILE_BUILD requires a multi-pass process; you need to build with one set of CFLAGS, then run the sample workload to get the data for your feedback directed optimizations, and then re-run the build with another set of CFLAGS. I think what we could to check for PROFILE_BUILD, and if it is set, do the first PROFILE_GEN / make test commands as part of the top-level Makefile's all: rule, and then do the normal build after that. It's a little kludgy, but does that sound acceptable to you? - Ted -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html