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This is an automatically generated e-mail. To reply, visit:
<a href="http://git.reviewboard.kde.org/r/100730/">http://git.reviewboard.kde.org/r/100730/</a>
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<div>Review request for KDevelop.</div>
<div>By Floris Ruijter.</div>
<p style="color: grey;"><i>Updated Feb. 24, 2011, 1:47 a.m.</i></p>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">rxx_allocator was according to my measurements done with kcachegrind, valgrind, duchainify and iostream. The allocator had three basic defects:
1) all allocated memory was deallocated whilst we need a lot of rxx_allocators (1 per file i presume?), so these blocks can be reused
2) it cleared the memory on a per block basis, but if not all of the block is used, then that is a waste of effort
3) it used realloc to manage the list of blocks, this isn't too bad but could cause a move of the list which is totaly unnecessary
i solved the problems mostly by making the blocks act as linked list nodes: a next pointer + a really long char array. deallocated blocks are kept in a static linked list, whilst actual rxx_allocators have their own(personal some would say)linked list of blocks. access to the deallocated blocks list is synchronized through a static QMutex.
the access could be threadsafe by using a thread local linked list of deallocated items too, but i don't think that'd be practical, the global static list is probably more effective (eventhough it requires locking) </pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing (updated)</h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">as mentioned i ran a file which only included iostream through duchainify which i callgrinded.
old: new:
pool::allocate ~450 000 000 ~7 000 000
all time spend in libkdev4cppparser:
~585 000 000 ~140 000 000
the pool::allocate numbers are both the 'inclusive' numbers
looking at the data for the amount of "operator new" calls I can see that the cost per call are pretty much the same but that the old implementation called it about 50x more.</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>languages/cpp/codecompletion/item.cpp <span style="color: grey">(b25d1ae)</span></li>
<li>languages/cpp/cppparsejob.cpp <span style="color: grey">(f4819f2)</span></li>
<li>languages/cpp/parser/ast.h <span style="color: grey">(0281c6b)</span></li>
<li>languages/cpp/parser/control.h <span style="color: grey">(0b06248)</span></li>
<li>languages/cpp/parser/listnode.h <span style="color: grey">(d1eda36)</span></li>
<li>languages/cpp/parser/parser.cpp <span style="color: grey">(281ad8d)</span></li>
<li>languages/cpp/parser/rxx_allocator.h <span style="color: grey">(f0159e9)</span></li>
<li>languages/cpp/parser/tests/test_parser.cpp <span style="color: grey">(de5f804)</span></li>
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<p><a href="http://git.reviewboard.kde.org/r/100730/diff/" style="margin-left: 3em;">View Diff</a></p>
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