On 26/11/2020 09:56, Mark Geisert wrote:
Cut mkimport elapsed time in half by forking each iteration of the two
time-consuming loops within. Only do this if more than one CPU is
present. In the second loop, combine the two 'objdump' calls into one
system() invocation to avoid a system() invocation per iteration.
Nice. Thanks for looking into this.
@@ -86,8 +94,18 @@ for my $f (keys %text) {
if (!$text{$f}) {
unlink $f;
} else {
- system $objcopy, '-R', '.text', $f and exit 1;
- system $objcopy, '-R', '.bss', '-R', '.data', "t-$f" and exit 1;
+ if ($forking && fork) {
+ # Testing shows parent does need to sleep a short time here,
+ # otherwise system is inundated with hundreds of objcopy processes
+ # and the forked perl processes that launched them.
+ my $delay = 0.01; # NOTE: Slower systems may need to raise this
+ select(undef, undef, undef, $delay); # Supports fractional seconds
+ } else {
+ # Do two objcopy calls at once to avoid one system() call overhead
+ system '(', $objcopy, '-R', '.text', $f, ')', '||',
+ $objcopy, '-R', '.bss', '-R', '.data', "t-$f" and exit 1;
+ exit 0 if $forking;
+ }
}
}
Hmm... not so sure about this. This seems racy, as nothing ensures that
these objcopies have finished before we combine all the produced .o
files into a library.
I'm pretty sure with more understanding, this whole thing could be done
better: For example, from a brief look, it seems that the t-*.o files
are produced by gas, and then we remove .bss and .data sections. Could
we not arrange to assemble these objects without those sections in the
first place?
