On Sun, Jun 21, 2009 at 7:00 AM, Alexandre Oliva<aol...@redhat.com> wrote: > On Jun 18, 2009, Alexandre Oliva <aol...@redhat.com> wrote: > >>> - Memory consumption in cc1/cc1plus at -Ox -g over that set of apps. > > I had to use a different machine for this test. The one I was using had > to be taken off line and moved, for reasons beyond my control, and I > probably won't be able to get into it to collect the results before I > hit the road later this week. Sorry. > > > For the total memory uses below, I moved gcc to gcc.actual in both the > trunk and vta install trees, and installed a new gcc script that ran > maxmem2.sh $0.actual "$@". > > I modified maxmem-pipe2.py to output to a named pipe, and for maxmem2.sh > to wait for the "cat >&2" from the named pipe to complete, just so that > I could correlate the memory use output with the command that produced > it. Without this change, in a number of cases the python script output > the totals after make had already printed the following command, which > got the output mangled and confusing. > > Having logged the build output of each of the trees that I had > configured before (-O2 is used for all of them), now with the maxmem > wrapper, I totaled the "total:" lines it printed for each of the builds, > resulting the values in the memory column below. > > # name mem(KiB) %Δ#1 which gflags > 1 g0-trunk 58114157 0 trunk -g0 > 2 g0 58114261 0 vta -g0 > 3 g-novt 59722133 2.77 vta -g -fno-$vt -fno-vta > 4 g-novta 59840445 2.97 vta -g -f$vt -fno-$vta > 5 g-novt-vta 59764629 2.84 vta -g -fno-$vt -f$vta > 6 g 59997781 3.24 vta -g -f$vt -f$vta > > Conclusions: generating debug information incurred a memory penalty of > nearly 3% before VTA, for a C-only optimized GCC build. > > Carrying VTA notes uses very little memory besides that which is > required to generate debug info without VT (0.07% more). > > Actually using VTA notes to emit debug information in the VT pass > increases maximum memory use, when compared with VT without VTA, by as > little as 0.26%. > > Wow, this was actually much better than I had anticipated.
The overhead of carrying VTA notes at -g0 vs not doing so would be the same 0.07%? I'm just curious because I try to be insisting on that we do exactly this ;) I wonder if the above figures apply to compiling a C++ application as well (I see a lot of VTA notes - more than 50% of all tree instructions - when compiling tramp3d for example). Thanks, Richard.
