On Wed, Mar 07, 2007 at 09:13:33PM +0100, Christian Franke wrote: >Christopher Layne wrote: >>On Fri, Mar 02, 2007 at 11:11:54AM -0800, Brian Dessent wrote: >>>Vinod Gupta wrote: >>> >>>>Cygwin was a slow by a factor of 3x. Is that normal? >>>Yes. Emulation of POSIX functions which do not exist on Windows is >>>expensive. Fork is especially bad, which is all you're really testing >>>there. >> >>Where is the *continual* fork in his script btw? > >There is no fork at all, the script uses only builtin shell commands. > >This command prints the fork() count of a script on Cygwin: > >$ strace bash ./script.sh | grep -c 'fork: 0 = fork()' > > >One reason for the slow execution of the script are >8000000 context >switches done by Cygwin. > >Bash calls sigprocmask() before starting each command, even for builtin >commands. >Cygwin's sigprocmask() unconditionally calls sig_dispatch_pending(). >This is necessary because POSIX requires that at least one pending >signal is dispatched by sigprocmask(). >sig_dispatch_pending() sends a __SIGFLUSH* to self and this causes 2 >thread context switches: main->sig->main. > >With the attached patch, sigprocmask() does nothing if the signal mask >is not changed. >This reduces the context switches to <5000. >(Patch is only intended for testing, it at least breaks above POSIX rule)
I removed the sig_dispatch_pending from handle_sigprocmask. I don't see any need for extra logic beyond that since you're doing tests that are already being done in set_signal_mask. I'll generate a snapshot with these changes for testing. Thanks for the patch. cgf -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/