On Friday, August 26, 2016 at 7:29:58 PM UTC+3, Bram Moolenaar wrote:
> Ramel Eshed wrote:
>
> > On Friday, August 26, 2016 at 12:02:38 AM UTC+3, Bram Moolenaar wrote:
> > > Ramel Eshed wrote:
> > >
> > > > On Thursday, August 11, 2016 at 3:08:01 AM UTC+3, Ramel Eshed wrote:
> > > > > On Thursday, August 11, 2016 at 2:19:38 AM UTC+3, Tony Mechelynck
> > > > > wrote:
> > > > > > There are other factors which are right there in the help:
> > > > > > - job_start() returns a Job object and doesn't wait for the job to
> > > > > > finish
> > > > > > - system() waits for the external command to finish and returns its
> > > > > > full stdout output as a string.
> > > > > >
> > > > > > I don't know Vim job control really well, but I seem to understand
> > > > > > that in order to compare system() timing and job control timing you
> > > > > > would have to set up callbacks to gather any output from the
> > > > > > channel,
> > > > > > and a callback to be called when the job ends (it may still write to
> > > > > > stdout after it exits), and measure the time from just before
> > > > > > job_start() to just after making sure that all output has been
> > > > > > collected and that the job has ended.
> > > > > >
> > > > > > You might even, for testing purposes, try to write a System() user
> > > > > > function to invoke the argument as a job and return its output as a
> > > > > > string, with the disadvantage that you would completely lose job
> > > > > > control asynchronism. But it would allow you a better comparison,
> > > > > > namely between old-fashioned system() and this new job-control-based
> > > > > > System().
> > > > > >
> > > > > > Best regards,
> > > > > > Tony.
> > > > >
> > > > > That's exactly what I've did:
> > > > >
> > > > > func! Job()
> > > > > let s:rt = reltime()
> > > > > let g:output = []
> > > > > let g:job = job_start(['/bin/sh', '-c', 'cat ' . expand('%')],
> > > > > {'out_cb': function('s:out_cb'), 'close_cb': function('s:close_cb')})
> > > > > endfunc
> > > > >
> > > > > func! s:out_cb(channel, msg)
> > > > > call add(g:output, a:msg)
> > > > > endfunc
> > > > >
> > > > > func! s:close_cb(channel)
> > > > > echo reltimestr(reltime(s:rt))
> > > > > "echo g:output
> > > > > endfunc
> > > > >
> > > > > " compare with:
> > > > >
> > > > > func! System()
> > > > > let s:rt = reltime()
> > > > > let g:output = systemlist('cat ' . expand('%'))
> > > > > echo reltimestr(reltime(s:rt))
> > > > > endfunc
> > > > >
> > > > > """""""""""""
> > > > > I checked it now on my Ubuntu at home - I still see the difference
> > > > > but now both are much faster so even the system() delay is not
> > > > > noticeable. Any idea what could cause the delay on my RHEL?
> > > > >
> > > > > BTW, if I remove the comment from the 'echo g:output' line in
> > > > > close_cb() the message is not displayed (actually, it depends on
> > > > > which command is running. for the 'cat' command above -there is no
> > > > > message).
> > > >
> > > > Hi Bram,
> > > >
> > > > Is it possible to make system() work the same way job_start (with a
> > > > shell) does? As I mentioned, I get a noticeable delay with system()
> > > > which I don't get when using job_start(['/bin/sh'...).
> > >
> > > Not sure if there is anything to improve. Would require finding out why
> > > it's slower and whether that can be fixed.
> > >
> > > You could add channel log commands in the code in various places to see
> > > what happens.
> >
> > My problem is not with the channel, the problem is that system() is
> > slower than the equivalent job_start(). You can run and compare the
> > results of Job() and System() functions in the attached file. They are
> > both doing the same thing ('echo aaa') but System() is ~5 times slower
> > than Job() on Ubuntu and x10 slower on RHEL5.5. On RHEL System() is
> > extremely slow, it takes about 0.2 seconds which cause Vim to hang.
>
> I understand that. The ch_log() and other functions cn be used anywhere
> in the Vim code. That is in the C code, not script. So it requires
> adding the log calls in several places in and around the system()
> implementation to find out where it spends time. This requires building
> Vim from the modified source.
>
> --
> hundred-and-one symptoms of being an internet addict:
> 91. It's Saturday afternoon in the middle of May and you
> are on computer.
>
> /// Bram Moolenaar -- b...@moolenaar.net -- http://www.Moolenaar.net \\\
> /// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
> \\\ an exciting new programming language -- http://www.Zimbu.org ///
> \\\ help me help AIDS victims -- http://ICCF-Holland.org ///
It looks like the delay is coming from the mch_delay(10L, TRUE) call inside the
for loop starting at line 4936 in os_unix.c:
/*
* Similar to the loop above, but only handle X events, no
* I/O.
*/
for (;;)
{
if (got_int)
{
/* CTRL-C sends a signal to the child, we ignore it
* ourselves */
# ifdef HAVE_SETSID
kill(-pid, SIGINT);
# else
kill(0, SIGINT);
# endif
got_int = FALSE;
}
# ifdef __NeXT__
wait_pid = wait4(pid, &status, WNOHANG, (struct rusage *)0);
# else
wait_pid = waitpid(pid, &status, WNOHANG);
# endif
if ((wait_pid == (pid_t)-1 && errno == ECHILD)
|| (wait_pid == pid && WIFEXITED(status)))
{
wait_pid = pid;
break;
}
/* Handle any X events, e.g. serving the clipboard. */
clip_update();
mch_delay(10L, TRUE);
}
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