You are absolutely right from a pragmatic perspective. However, having 100 refreshes top off a relatively recent CPU is quite worrisome and IMHO should not be dismissed lightly as it could manifest in other contexts as well. FWIW I did a program which had a similar feature in Qt over four years ago (with 100Hz refreshes for several concurrent timers) and its CPU usage was always less than 3% at that time. This either suggests that Tcl/Tk is a total hog or that there is a bug in a code somewhere (or both).
Hence me bringing this up...
Ico
-----Original Message----- From: Hans-Christoph Steiner [mailto:hans@eds.org] Sent: Monday, February 19, 2007 10:22 PM To: ico@vt.edu Cc: pd-dev@iem.at Subject: Re: [PD-dev] tcl/tk 8.5, antialising, and large fonts lead to huge cpu overhead bug?
Sounds like you are charting new territory. I haven't worked with Tcl/Tk 8.5 yet, but I think a couple people on the list have.
I don't know of any reason to update a GUI object more than 100 Hz since that's about the max for screen refreshes. 10 Hz is probably faster than we can perceive numbers anyway.
.hc
On Feb 18, 2007, at 11:03 PM, ico@vt.edu wrote:
All right, unlike my previous e-mail this is perhaps not a bug, but an oddity. Nonetheless, it would be nice to know at least where it is stemming from so that I can contribute code in the right place...
I've encountered unusual spike in cpu use when using antialiased tcl/tk 8.5 (IIRC it also affects other antialiasing-enabled tcl/tk releases) in conjunction with large fonts. I for instance use this for my performers so that they can clearly read info even when positioned at some distance from the display monitor/LCD.
One quick example would be to use a large font counter which counts 1/100ths of a second using metro and displaying it in a number2 object. This results in a 80+% (!) CPU utilization on an Athlon 64 3000+. Lowering metro to 1/10th of second drops CPU use below 5%. Similarly making font smaller does the same. Font size used is in this case is just about anything above 72.
Any ideas how to circumvent this problem? Is this due to antialiasing inefficiency in tcl/tk or some other reason? If I can be pointed in the right direction, I'll gladly provide patches...
Best wishes,
Ivica Ico Bukvic, D.M.A. Composition, Music Technology, CCTAD, CHCI Virginia Tech Department of Music Blacksburg, VA 24061-240 (540) 231-1137 (540) 231-5034 (fax) ico.bukvic.net
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