Hi, For almost three months now, we've had graphs following the amount of memory used by the linker on Windows builders during PGO builds. The result can be seen here:
http://graphs.mozilla.org/graph.html#tests=[[205,63,8]]&sel=none&displayrange=90&datatype=running The first thing to notice in here is the 13 spikes down. The last one is bug 860371. I wasn't aware of any of the 12 others. It might be worth looking into them to understand why they happen. Interestingly, my dev-tree-management archive doesn't show any notification for these (except for the last one), nor for any of the progressive "regressions". The second thing to notice is the graph starts a little over 3.2GB and ends a little below 3.6GB, for a 360MB growth in less than three months. At this pace, we'll run out of address space around june or july. So, it's this time of year again. But for once, we can get things in order before they blow up, not when it's too late and we have to rush things. And as bug 860371 reminded us (look for recent massive regressions accross the board on dev-tree-management), PGO is a big deal. Note bug 860371 only removed the data used by the compiler during PGO builds, so link time code generation was still happening. But we already knew LTCG alone wasn't much of a win. We need to look back (and looking around the times where the graph jumps up might be good starting points) and see what can be accounted for this growth. I suspect part of it is due to newly imported code. Possibly, this new code might not need to be PGOed. There may be other areas that can be unPGOed without much of an impact, like we did last time. Are there any volunteers? I think we need to start thinking how to make PGO opt-in instead of opt-out, while keeping performance where it is now. We also need to ensure we do get regression notifications on dev-tree-management. If I hadn't looked at the graph after bug 860371 blew things up, I wouldn't have noticed we were getting in the dangerous zone again. Mike _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
