From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerald Pfeifer To: Mark Mitchell , Daniel Berlin Cc: , Joe Buck , "gcc@gcc.gnu.org" , "gcc-patches@gcc.gnu.org" Subject: Re: C++ compile-time regressions Date: Tue, 07 Aug 2001 07:54:00 -0000 Message-id: References: <87y9p2rxny.fsf@cgsoftware.com> X-SW-Source: 2001-08/msg00437.html On Thu, 2 Aug 2001, Mark Mitchell wrote: > I think we're tackling this from the wrong angle. GCC uses about > 3 to 4 times as much memory as it needs to, really, and our garbage > collector touches too many pages. Well, I think we need to tackle it from several angles. :-) Right now, both compile-time and run-time performance are worse than GCC 2.95 (even if we tune for either one). > I know how to fix these problems, I think, and I expect to start > working on them soonish. That's excellent news, thanks! > Anyhow, I guess I think we've done enough for now. Daniel seems to have a promising patch, (a first draft of) which seems very non-invasive and simple; this might be an excellent candidate for GCC 3.0.2. On Thu, 2 Aug 2001, Daniel Berlin wrote: > BTW, i've gotten the performance problem down using a slightly > modified heuristic from integrate.c. On the last run, the compile > times were about the same as 200 insns, but the performance was *much* > better (we're down to about 10% speed loss). Excellent. > When your performance gets shot to hell, it's always being caused by > not inlining things. I.E. at 100 insns, *::begin and *::end are taking > >50% of the runtime, because they aren't being inlined. I guessed that something extremely bad like this was going on, because performance was getting *that* bad. Good to see both issues (compile-time and run-time performance) being addressed. :-) Gerald -- Gerald "Jerry" pfeifer@dbai.tuwien.ac.at http://www.dbai.tuwien.ac.at/~pfeifer/