<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><span class="vcard"><a class="email" href="mailto:kim.walisch@gmail.com" title="Kim Walisch <kim.walisch@gmail.com>"> <span class="fn">Kim Walisch</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WORKSFORME - Clang/OpenMP schedule(dynamic): severe scaling issue, up to 2.5x slower than GCC/OpenMP"
href="https://bugs.llvm.org/show_bug.cgi?id=49588">bug 49588</a>
<br>
<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>WORKSFORME
</td>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WORKSFORME - Clang/OpenMP schedule(dynamic): severe scaling issue, up to 2.5x slower than GCC/OpenMP"
href="https://bugs.llvm.org/show_bug.cgi?id=49588#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WORKSFORME - Clang/OpenMP schedule(dynamic): severe scaling issue, up to 2.5x slower than GCC/OpenMP"
href="https://bugs.llvm.org/show_bug.cgi?id=49588">bug 49588</a>
from <span class="vcard"><a class="email" href="mailto:kim.walisch@gmail.com" title="Kim Walisch <kim.walisch@gmail.com>"> <span class="fn">Kim Walisch</span></a>
</span></b>
<pre>I was able to fix my particular scaling issue by using
schedule(monotonic:dynamic, 1) instead of schedule(dynamic, 1) (which is the
same as schedule(nonmonotonic:dynamic, 1)).
My algorithms work best when the iterations are executed in "increasing logical
iteration order". This partially explains why the default schedule(dynamic, 1)
is not well suited for my particular use case as iterations may be executed in
any order. I will note however that GCC's schedule(nonmonotonic:dynamic, 1)
scales very nicely in my benchmarks, so I do think that there is room for
improvement in Clang/libomp's schedule(nonmonotonic:dynamic, 1) implementation.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>