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Re: [tree-ssa PATCH] Pick memory consumption low hanging fruit
> > So it seems that tree-pre is doing something that keeps a lot of
> > memory from being gc-ed.
> First, As i've pointed out, PRE doesn't do any ggc_alloc's during PRE anymore,
> the only thing it ggc_alloc's is a <100 byte structure (it's probably 20
> or 40) to store some info about the expression. It may inadvertently
> cause ggc_allocs because of how tree-ssa works (IE resizing and clearing
> ggc_alloc'd varrays), but it's not in my code.
> Second, Also, I tried it, and at -O2, I can't get memory to go above 250
> meg WITH PRE on.
> I can at -O3, with or without PRE.
> This is on fedora core 1. Maybe something changed in glibc's memory
> I have no local changes save a 2 line fix for Jeff Law's problem.
> My mem-report looks like this, *with* PRE, at -O2
In more oddness, I updated the CVS tree (it was last updated when i
committedmy last PRE patches) to today, and the numbers changed.
It now hits 330 meg, but the mem report doesn't show much different (13
8 1856k 313k 41k
16 3032k 688k 44k
32 18M 2984k 202k
64 11M 9057k 106k
128 4096 1024 32
256 6960k 6535k 47k
512 4640k 4456k 31k
1024 8960k 8698k 61k
2048 12k 6144 84
4096 8192 8192 56
8192 24k 24k 84
16384 16k 16k 28
32768 320k 320k 280
65536 64k 64k 28
131072 384k 384k 84
262144 256k 256k 28
116 41M 29M 331k
24 32M 7329k 391k
12 4612k 508k 76k
40 10M 4025k 107k
Total 145M 74M 1443k
I really hope our GC isn't this variant that we range from a high water
mark of 250 to 750 meg depending on random factors.