[Tcl-bugs] [ tktoolkit-Bugs-1692395 ] Poor listbox performance in Tk 8.5a6

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Bugs item #1692395, was opened at 2007-04-01 18:17
Message generated for change (Comment added) made by nemethi
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Category: 09. [listbox]
Group: development: 8.5a6
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Csaba Nemethi (nemethi)
Assigned to: Allen Flick (caflick)
Summary: Poor listbox performance in Tk 8.5a6

Initial Comment:
The following simple script demonstrates a siginificant listbox performance regression in Tk 8.5a6:

pack [listbox .lb]
puts [time {
    for {set n 0} {$n < 100000} {incr n} {
        .lb insert end "This is item #$n"
    }
}]

On my rather slow Linux box (running SuSE Linux 10.0), this script produces the output

1793963 microseconds per iteration

Compare this with the time needed by Tk 8.4.13:

1126718 microseconds per iteration

This is an unacceptable performance regression.

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>Comment By: Csaba Nemethi (nemethi)
Date: 2007-04-05 23:47

Message:
Logged In: YES 
user_id=317958
Originator: YES

I have rebuilt Tk 8.5a6, using --enable-xft=no.  The test with this new Tk
8.5a6 version produces the output

1227183 microseconds per iteration

This is just a bit slower than with Tk 8.4.13.

This test shows that the use of the Xft library (which is activated by
default in Tk 8.5a6) has a serious negative impact on the performance of
the listbox widget.

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