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Re: [PATCH] Temporarily enable ac_fold_checking for --enable-checking=yes.
On Sat, 2007-06-23 at 13:30 -0600, Jeffrey Law wrote:
> Other approaches might look for a slick way to cut down on the system
> overhead necessary to run a single testfile -- while 20061226-1 takes a
> lot of time, we also burn an insane amount of time on all the small
> tests with the multiple shell, compiler, assembler, linker invocations.
> We've got some hacks to cut down (don't run the loop related iterations
> if there are no loops, don't re-run the executable if it was unchanged
> when the new options, etc). But there's no systematic approach to
> avoiding useless work. I'm really not even sure where to start with
> this angle, but last I looked with oprofile, we burned an inordinate
> amount of time firing up shells, fork/exec, gcc 8 or more times per
> torture test... God help you if you happened to use a system with a
> slow process startup (hpux, solaris).
As shown here:
http://gcc.gnu.org/ml/gcc-patches/2007-06/msg01913.html
For make bootstrap 'sys' time is 10% of 'user' time
while for make check it is about 36% of 'user' on x86_64-linux native
so this issue is still there.
For those with multicore machines, just splitting a bit the
test sets can probably gain a 2x factor in wall clock time on
a 4 cores make -k -j 4 check (and 3-4x factor for C only).
Laurent