|Summary:||Showing large plain-text files is extremely slow|
|Product:||WebKit||Reporter:||Benjamin Meyer <ben>|
|Component:||Layout and Rendering||Assignee:||QtWebKit Unassigned <webkit-qt-unassigned>|
|Severity:||Major||CC:||eike.ziller, jturcotte, kenneth, kling, laszlo.gombos|
|Version:||528+ (Nightly build)|
|Bug Depends on:|
Description Benjamin Meyer 2008-07-16 07:45:13 PDT
What steps will reproduce the problem? 1. dd if=/dev/urandom of=/tmp/test.txt bs=1024 count=256 2. go to uri file:///tmp/test.txt What is the expected output? What do you see instead? Mozilla shows this file in about 1 second. QtWebKit from Qt 4.4 Please provide any additional information below. Showing this file takes about 60 seconds on my machine. I tracked down the issue to the fact that in bidi.cpp we are calling nextBreakablePosition over and over which constructs a QTextBoundryFinder
Comment 1 Benjamin Meyer 2008-07-16 07:50:06 PDT
I started hacking around and made a branch that passes all of the tests and re-uses the iterator when possible, but it is a bit of a hack and when you enable the other iterator caches there are three failures which doesn't make any sense... And it can still crash an iterator is created, the string is deleted a new string is created at the same location in memory, but with a different lenght and a new iterator is created with it. We should just see about re-using the same iterator upstream. Branch: http://code.staikos.net/cgi-bin/gitweb.cgi?p=webkit;a=shortlog;h=bmeyer/fasttext Diff: http://code.staikos.net/cgi-bin/gitweb.cgi?p=webkit;a=blobdiff;f=WebCore/platform/qt/TextBreakIteratorQt.cpp;h=94aafdba5e8fd2e261caa4b446756112e1a3c2c6;hp=88b96808650ed290ea328208157d2f965089d39e;hb=95c45c80fc64841cfc262facaba34750b9ca5138;hpb=af6eca2c5a5ec7e5a462ad211f8f1e3cb9bdef86
Comment 2 Benjamin Meyer 2008-07-16 09:22:37 PDT
Probably worth looking into what the average length is. Maybe we could get rid of the buffer
Comment 3 Kenneth Rohde Christiansen 2009-10-04 07:31:33 PDT
There have recently been some commits that could improve this: https://bugs.webkit.org/show_bug.cgi?id=29092 Can you tell me if this is still an issue?
Comment 4 Jocelyn Turcotte 2009-12-02 02:13:46 PST
Created attachment 44137 [details] Large text file Example generated using: dd if=/dev/random bs=1024 count=256 | base64 > large.txt The bug is still present, reloading this file locks the browser for 20 seconds, it loads instantly in firefox.
Comment 5 Jocelyn Turcotte 2010-03-03 06:12:00 PST
This bug has to be fixed for QtWebKit 2.0
Comment 6 Andreas Kling 2010-03-10 10:03:52 PST
*** This bug has been marked as a duplicate of bug 31719 ***
Comment 7 Benjamin Meyer 2010-03-10 11:52:35 PST
Shouldn't that one be a duplicate of this issue as this is the older issue?
Comment 8 Andreas Kling 2010-03-10 17:21:12 PST
I opted for keeping the other one since it had more useful information.