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<h1>Hoard Frequently Asked Questions</h1>
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<ul class="minitoc">
<li>
<a href="#%0AWhat+kind+of+applications+will+Hoard+speed+up%3F%0A">
What kind of applications will Hoard speed up?
</a>
</li>
<li>
<a href="#%0A++I%27m+using+the+STL+but+not+seeing+any+performance+improvement.+Why+not%3F%0A++">
I'm using the STL but not seeing any performance improvement. Why not?
</a>
</li>
<li>
<a href="#%0AWhat+systems+does+Hoard+work+on%3F%0A">
What systems does Hoard work on?
</a>
</li>
<li>
<a href="#%0AHave+you+compared+Hoard+with+SmartHeap+SMP%3F%0A">
Have you compared Hoard with SmartHeap SMP?
</a>
</li>
<li>
<a href="#%0A++++++Have+you+compared+Hoard+against+mtmalloc+or+libumem%3F%0A">
Have you compared Hoard against mtmalloc or libumem?
</a>
</li>
<li>
<a href="#%0ACan+I+use+Hoard+with+a+commercial+application%3F%0A">
Can I use Hoard with a commercial application?
</a>
</li>
</ul>
</div>
<a name="N1000C"></a><a name="%0AWhat+kind+of+applications+will+Hoard+speed+up%3F%0A"></a>
<h2 class="boxed">
What kind of applications will Hoard speed up?
</h2>
<div class="section">
<p>
Hoard will always improve the performance of multithreaded programs
running on multiprocessors that make frequent use of the heap (calls
to malloc/free or new/delete, as well as many STL functions). Because
Hoard avoids false sharing, Hoard also speeds up programs that only
occasionally call heap functions but access these objects frequently.
</p>
</div>
<a name="N10016"></a><a name="%0A++I%27m+using+the+STL+but+not+seeing+any+performance+improvement.+Why+not%3F%0A++"></a>
<h2 class="boxed">
I'm using the STL but not seeing any performance improvement. Why not?
</h2>
<div class="section">
<p>
In order to benefit from Hoard, you have to tell STL to use malloc instead of its internal custom memory allocator:
</p>
<pre class="code">
typedef list<unsigned int, malloc_alloc> mylist;
</pre>
</div>
<a name="N10024"></a><a name="%0AWhat+systems+does+Hoard+work+on%3F%0A"></a>
<h2 class="boxed">
What systems does Hoard work on?
</h2>
<div class="section">
<p>
Hoard has been successfully tested on numerous Windows, Linux and
Solaris systems, including a 4-processor x86 box running Windows
NT/2000, a 4-processor x86 box running RedHat Linux 6.0 and 6.1, and a
16-processor Sun Enterprise server running Solaris.
</p>
</div>
<a name="N1002D"></a><a name="%0AHave+you+compared+Hoard+with+SmartHeap+SMP%3F%0A"></a>
<h2 class="boxed">
Have you compared Hoard with SmartHeap SMP?
</h2>
<div class="section">
<p>
We tried SmartHeap SMP but it did not work on our Suns (due to an
apparent race condition in the code).
</p>
</div>
<a name="N10036"></a><a name="%0A++++++Have+you+compared+Hoard+against+mtmalloc+or+libumem%3F%0A"></a>
<h2 class="boxed">
Have you compared Hoard against mtmalloc or libumem?
</h2>
<div class="section">
<p>
Yes. Hoard is much faster than either. For example, here's an
execution of threadtest on Solaris:
</p>
<table class="ForrestTable" cellspacing="1" cellpadding="4">
<tr>
<td colspan="1" rowspan="1">Default:</td>
<td colspan="1" rowspan="1">4.60 seconds</td>
</tr>
<tr>
<td colspan="1" rowspan="1">Libmtmalloc:</td>
<td colspan="1" rowspan="1">6.23 seconds</td>
</tr>
<tr>
<td colspan="1" rowspan="1">Libumem:</td>
<td colspan="1" rowspan="1">5.47 seconds</td>
</tr>
<tr>
<td colspan="1" rowspan="1">Hoard 3.2:</td>
<td colspan="1" rowspan="1">1.99 seconds</td>
</tr>
</table>
</div>
<a name="N10077"></a><a name="%0ACan+I+use+Hoard+with+a+commercial+application%3F%0A"></a>
<h2 class="boxed">
Can I use Hoard with a commercial application?
</h2>
<div class="section">
<p>
Yes. Hoard is available under two licenses. The first license is the
GNU General Public License. That license is free, but it requires you
to open-source your application. The second option is to purchase a
license from the University of Texas at Austin. Click the "Licensing Info"
link on the left for more information.
</p>
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