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<title>GNU libgomp: GOMP_SPINCOUNT</title>

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<a name="GOMP_005fSPINCOUNT-_002d_002d-Set-the-busy_002dwait-spin-count"></a>
<h3 class="section">3.16 <code>GOMP_SPINCOUNT</code> &ndash; Set the busy-wait spin count</h3>
<a name="index-Environment-Variable-15"></a>
<a name="index-Implementation-specific-setting-4"></a>
<dl compact="compact">
<dt><em>Description</em>:</dt>
<dd><p>Determines how long a threads waits actively with consuming CPU power
before waiting passively without consuming CPU power.  The value may be
either <code>INFINITE</code>, <code>INFINITY</code> to always wait actively or an
integer which gives the number of spins of the busy-wait loop.  The
integer may optionally be followed by the following suffixes acting
as multiplication factors: <code>k</code> (kilo, thousand), <code>M</code> (mega,
million), <code>G</code> (giga, billion), or <code>T</code> (tera, trillion).
If undefined, 0 is used when <code>OMP_WAIT_POLICY</code> is <code>PASSIVE</code>,
300,000 is used when <code>OMP_WAIT_POLICY</code> is undefined and
30 billion is used when <code>OMP_WAIT_POLICY</code> is <code>ACTIVE</code>.
If there are more OpenMP threads than available CPUs, 1000 and 100
spins are used for <code>OMP_WAIT_POLICY</code> being <code>ACTIVE</code> or
undefined, respectively; unless the <code>GOMP_SPINCOUNT</code> is lower
or <code>OMP_WAIT_POLICY</code> is <code>PASSIVE</code>.
</p>
</dd>
<dt><em>See also</em>:</dt>
<dd><p><a href="OMP_005fWAIT_005fPOLICY.html#OMP_005fWAIT_005fPOLICY">OMP_WAIT_POLICY</a>
</p></dd>
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