Re: [PATCH] Cygwin: Speed up mkimport

[Achim Gratz]

Mark Geisert writes:
> + # 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;

That doesn't do what you think it does.  It in fact increases the
overhead since it'll start a shell that runs those two commands sand
will even needlessly start the first objcopy in a subshell.


Regards,
Achim.
-- 
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Re: [PATCH] Cygwin: Speed up mkimport

[Mark Geisert]

Previously, 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

 ^^^
That should say objcopy.  The code is correct though.

..mark

[PATCH] Cygwin: Speed up mkimport

[Mark Geisert]

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.

---
 winsup/cygwin/mkimport | 34 ++
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/winsup/cygwin/mkimport b/winsup/cygwin/mkimport
index 2b08dfe3d..919dc305b 100755
--- a/winsup/cygwin/mkimport
+++ b/winsup/cygwin/mkimport
@@ -47,6 +47,9 @@ for my $sym (keys %replace) {
 $import{$fn} = $imp_sym;
 }
 
+my $ncpus = `grep -c ^processor /proc/cpuinfo`;
+my $forking = $ncpus > 1; # Decides if loops below should fork() each iteration
+
 for my $f (keys %text) {
 my $imp_sym = delete $import{$f};
 my $glob_sym = $text{$f};
@@ -56,25 +59,30 @@ for my $f (keys %text) {
$text{$f} = 0;
 } else {
$text{$f} = 1;
-   open my $as_fd, '|-', $as, '-o', "$dir/t-$f", "-";
-   if ($is64bit) {
-   print $as_fd <