On 11/24/2015 12:04 PM, Simon Glass wrote:
Hi Stephen,
On 23 November 2015 at 21:44, Stephen Warren <swar...@wwwdotorg.org> wrote:
On 11/23/2015 06:45 PM, Simon Glass wrote:
On 22 November 2015 at 10:30, Stephen Warren <swar...@wwwdotorg.org> wrote:
On 11/21/2015 09:49 AM, Simon Glass wrote:
OK I got it working thank you. It is horribly slow though - do you
know what is holding it up? For me to takes 12 seconds to run the
(very basic) tests.
..
I put a bit of time measurement into run_command() and found that on my
system at work, for p.send("the shell command to execute") was actually
(marginally) slower on sandbox than on real HW, despite real HW being a
115200 baud serial port, and the code splitting the shell commands into
chunks that are sent and waited for synchronously to avoid overflowing
UART FIFOs. I'm not sure why this is. Looking at U-Boot's console, it
seems to be non-blocking, so I don't think termios VMIN/VTIME come into
play (setting them to 0 made no difference), and the two raw modes took
the same time. I meant to look into pexpect's termios settings to see if
there was anything to tweak there, but forgot today.
I did do one experiment to compare expect (the Tcl version) and pexpect.
If I do roughly the following in both:
spawn u-boot (sandbox)
wait for prompt
100 times:
send "echo $foo\n"
wait for "echo $foo"
wait for shell prompt
send "reset"
wait for "reset"
send "\n"
... then Tcl is about 3x faster on my system (IIRC 0.5 vs. 1.5s). If I
remove all the "wait"s, then IIRC Tcl was about 15x faster or more.
That's a pity. Still, I'm sure as heck not going to rewrite all this in
Tcl:-( I wonder if something similar to pexpect but more targetted at
simple "interactive shell" cases would remove any of that overhead.
It is possible that we should use sandbox in 'cooked' mode so that
lines an entered synchronously. The -t option might help here, or we
may need something else.
I don't think cooked mode will work, since I believe cooked is
line-buffered, yet when U-Boot emits the shell prompt there's no \n
printed afterwards.
FWIW, I hacked out pexpect and replaced it with some custom code. That
reduced by sandbox execution time from ~5.1s to ~2.3s. Execution time
against real HW didn't seem to be affected at all. Some features like
timeouts and complete error handling are still missing, but I don't
think that would affect the execution time. See my github tree for the
WIP patch.
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