Re: Plotting with 3.2.0 on Windows is SLOOOOOOWWWW

[Tatsuro MATSUOKA]

Hello

**For tracking this issue, 
http://www.nabble.com/Plotting-with-3.2.0-on-Windows-is-SLOOOOOOWWWW-td24703690.html

***********
I have got a great hint to overcome this issue.  

I have changed pipe buffer size of CreatPipe in octave_popen2 .  The times of 
he Disk access was
reduced however no speed up is observed.  

Today I have !!!!suddenly!!!! gotten an idea the gnuplot process may be very 
slow. Then it I pressed
CTRL+ALT+DEL keys and execute the windows task manager.  

When the following  command executing,
N = 100;
n = 2;
m = 2;
tic
for i = 1:n*m
    x = rand (2,N);
    subplot (n,m,i);
    plot (x(1,:),x(2,:)); 
end
toc

octave-3.2.0 occupied 99% cpu activity and thus I guessed that the speed 
gnuplot made slower and thus
led to slooooow plotting.  

Next before the above command by Matthias Brennwald I have execute the 
following command on
octave-3.2.0.

fplot(@sin, [0 2*pi])

After that I pressed CTRL+ALT+DEL keys and execute the task manager, selected 
'Process' tab, and found
the process of gnuplot.exe.  Then I clicked gnuplot.exe by a right mouse button 
and change priority of
the process of gnuplot to be increased by one grade.

The above priority setting gave 2 second for the whole plotting by the command 
of Matthias Brennwald.

The reason why the slowness did not occur in the computer in my university may 
come from that the cpu
of the computer is hyper-threaded so that even if 1 logical core occupied by 
octave process, the
gnuplot can work at enough speed the otherlogical cpu.

If one can control process priority of the child process (in this case of 
gnuplot) can be controled   
.

In the case of the cygwin the child process via pipe may be given higher 
priority than that in
windows.     

The stories the above have not been completely proved but the results give us 
important hint to
overcome this issue.

I will consult Microsoft pages for windows API functions and consider the patch.

Comments to this post are highly appreciated.

Regards

Tatsuro


--- "John W. Eaton" wrote:

> On 30-Jul-2009, Tatsuro MATSUOKA wrote:
> 
> | The above change gives errors;
> | 
> | error: __gnuplot_get_var__: Need mkfifo that is not implemented under 
> Windows
> | error: called from:
> | error:   
> C:\Programs\Octave\3.2.0_gcc-4.3.0\share\octave\3.2.0\m\plot\__gnuplot_get_var__.m
>  at
> line
> | 52, column 7
> 
> OK, so the current plotting scripts actually require 2-way
> communication with gnuplot to do anything useful.  So I guess you'll
> need to debug this problem in some other way.
> 
> jwe
> 


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