Hi Alan, Laurent I can't say I have much to add. It wasn't obvious to me where the lag was last time i looked, but I agree it is an issue
I haven't done much plplot work for some time, but when I can i will look at this. If anyone has any suggestions I would be keen to hear. Phil Sent from my Windows 10 phone From: Alan W. Irwin Sent: 15 November 2016 21:22 To: Laurent Berger Cc: PLplot development list Subject: Re: [Plplot-devel] The wxwidgets device driver speed/idle time On 2016-11-15 14:59+0100 Laurent Berger wrote: > Hi Alan, > > I haven't got qt installed. > My results looks like yours results : > > lb@mp12-lb:~/plplot.git/examples/c++$ time ./x01 -dev wxwidgets -np > PLplot library version: 5.11.1 > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 103: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 138: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 103: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 138: > Having multiple values in <test> isn't supported and may not work as expected > > real 0m0.407s > user 0m0.108s > sys 0m0.016s > lb@mp12-lb:~/plplot.git/examples/c++$ time ./x01 -dev wxwidgets -np > PLplot library version: 5.11.1 > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 103: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 138: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 103: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 138: > Having multiple values in <test> isn't supported and may not work as expected > > real 0m10.997s > user 0m0.064s > sys 0m0.040s > lb@mp12-lb:~/plplot.git/examples/c++$ time ./x01 -dev xwin -np > PLplot library version: 5.11.1 > > real 0m0.122s > user 0m0.056s > sys 0m0.020s > lb@mp12-lb:~/plplot.git/examples/c++$ time ./x01 -dev xwin -np > PLplot library version: 5.11.1 > > real 0m0.122s > user 0m0.060s > sys 0m0.016s > lb@mp12-lb:~/plplot.git/examples/c++$ time ./x01 -dev xcairo -np > PLplot library version: 5.11.1 > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 103: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 138: > Having multiple values in <test> isn't supported and may not work as expected > > real 0m0.125s > user 0m0.088s > sys 0m0.016s > lb@mp12-lb:~/plplot.git/examples/c++$ time ./x01 -dev xcairo -np > PLplot library version: 5.11.1 > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 103: > Having multiple values in <test> isn't supported and may not work as expected > Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 138: > Having multiple values in <test> isn't supported and may not work as expected > > real 0m0.128s > user 0m0.084s > sys 0m0.020s > lb@mp12-lb:~/plplot.git/examples/c++$ Hi Laurent: Thanks very much for the above report. Your timing results verify mine and show that -dev wxwidgets sometimes has very poor "real" timing results even though the actual cpu times indicated by the sum of "user" + "sys" are quite fast and consistent. For this case > real 0m10.997s > user 0m0.064s > sys 0m0.040s the sum of user + sys is 0.104 seconds so that means for this test the cpu was idle for 10.893 seconds out of the 10.997 seconds or 99.05 per cent of the time which is equivalent to two (!) orders of magnitude slowdown. Since your results and mine confirm the problem for a wide range of Linux kernel versions, my working hypothesis is these excessive idle times/slowdowns are due to the inefficient way that Linux kernel IPC is being used to implement the necessary two-way communication between -dev wxwidgets and the wxPLviewer application on Linux. Gaining two orders of magnitude in speed is certainly an attractive goal for the wxwidgets device/wxPLviewer combination so I am tempted to immediately start reviewing the Linux kernel IPC use between -dev wxwidgets and wxPLviewer. However, my current knowledge of Linux kernel IPC is small, and I have many other PLplot issues on my plate at the moment so I will have to delay this for quite a while. Thus, there is an opportunity for someone else to contribute substantially here if they have some knowledge about the most efficient way to use Linux kernel IPC or want to learn more about that interesting topic. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------------ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
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