[VM] Should probably add -fno-gcse to the GCC flags
Ned Konz
ned at bike-nomad.com
Wed Aug 6 19:52:03 UTC 2003
The GCC manual recommends trying the -fno-gcse (omit global common
subexpression extraction) flag when you're using the computed gotos.
Since we're doing this in the gnuified interpreters, I figured I'd
try it.
So I just recompiled the one file (gnu-interp.c) with the -fno-gcse
option added to the
-O2 -fomit-frame-pointer
options that were already there.
Here's the results:
0 tinyBenchmarks
with -fno-gcse in gnu-interp
'114081996 bytecodes/sec; 4165025 sends/sec'
'115315315 bytecodes/sec; 4086882 sends/sec'
'113374667 bytecodes/sec; 4177005 sends/sec'
without -fno-gcse in gnu-interp
'114081996 bytecodes/sec; 3942639 sends/sec'
'115315315 bytecodes/sec; 3996896 sends/sec'
'112775330 bytecodes/sec; 3942639 sends/sec'
As you can see, there are small but measurable differences in speed.
This is on an AMD Duron processor, under Linux, with the SourceForge
VM sources.
--
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE
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