The garbage collector in Maple 17 is capable of running multiple threads to take advantage of multiple cores.  This can speed up the collector significantly.  Although the collector is only responsible for a fraction of Maple's total running time, this can still lead to running times reduced by up to 10%.  These speed ups require no changes to user code.

There are 2 kernelopts that can control the parallel collector.

gcmaxthreads controls the maximum number of threads that the parallel garbage collector will use.

gcthreadmemorysize controls how many threads Maple will use for a collection.  The number of bytes allocated is divided by the value assigned to gcthreadmemorysize to determine the number of threads.

$\mathrm{restart}$

$$\begin{gathered} \mathbf{if} \left(\mathrm{kernelopts}\left(\mathrm{wordsize}\right) \= 32\right) \mathbf{then} \\ \mathrm{upperBound} ≔ 2\cdot 10\^7\; \\ \mathbf{else} \\ \mathrm{upperBound} ≔ 10\^8\; \\ \mathbf{end} \mathbf{if}\: \end{gathered}$$

$\mathrm{data} ≔ \left[\mathrm{seq}\left(i\, i \= 1 .. \mathrm{upperBound}\right)\right]\:$

$$\begin{gathered} p:=\mathbf{proc}\left(\right) \\ \mathbf{local} i\; \\ \mathbf{for} i \mathbf{to} 100 \\ \mathbf{do} \\ \mathrm{gc}\left(\right) \\ \mathbf{end} \mathbf{do} \\ \mathbf{end} \mathbf{proc}\: \end{gathered}$$

$\mathrm{kernelopts}\left(\mathrm{gcmaxthreads}\=1\right)\:$$\mathrm{t1}\left[1\right]≔\mathrm{time}\left[\mathrm{real}\right]\left(p\left(\right)\right)\:$

$\mathrm{kernelopts}\left(\mathrm{gcmaxthreads}\=2\right)\:$$\mathrm{t1}\left[2\right]≔\mathrm{time}\left[\mathrm{real}\right]\left(p\left(\right)\right)\:$

$\mathrm{kernelopts}\left(\mathrm{gcmaxthreads}\=4\right)\:$$\mathrm{t1}\left[4\right]≔\mathrm{time}\left[\mathrm{real}\right]\left(p\left(\right)\right)\:$

$\mathrm{Statistics}:-\mathrm{ColumnGraph}\left(\left[\mathrm{t1}\[1\]\,\mathrm{t1}\[2\]\,\mathrm{t1}\[4\]\right]\,\mathrm{datasetlabels}\=\left[''One\; Thread''\,''Two\; Threads''\,''Four\; Threads''\right]\,\mathrm{labels}\=\left[''''\,''Seconds''\right]\,\mathrm{gridlines}\right)$

$\mathrm{restart}$

$d:=\left[\mathrm{seq}\left(\mathrm{randpoly}\left(\left[x\,y\,z\right]\,\mathrm{dense}\,\mathrm{degree}\=12\right)\,i\=1..10000\right)\right]\:$

$$\begin{gathered} f:=\mathbf{proc}\left(\right) \\ \mathbf{local} i\; \\ \mathrm{map}\left(i\→\mathrm{int}\left(i\,x\right)\,d\right) \\ \mathbf{end} \mathbf{proc}\: \end{gathered}$$

$\mathrm{kernelopts}\left(\mathrm{gcmaxthreads}\=1\right)\:$

$\mathrm{t2}\left[1\right]≔\mathrm{time}\left[\mathrm{real}\right]\left(f\left(\right)\right)\:$

$\mathrm{kernelopts}\left(\mathrm{gcmaxthreads}\=2\right)\:$

$\mathrm{t2}\left[2\right]≔\mathrm{time}\left[\mathrm{real}\right]\left(f\left(\right)\right)\:$

$\mathrm{kernelopts}\left(\mathrm{gcmaxthreads}\=4\right)\:$

$\mathrm{t2}\left[4\right]≔\mathrm{time}\left[\mathrm{real}\right]\left(f\left(\right)\right)\:$

$\mathrm{Statistics}:-\mathrm{ColumnGraph}\left({\left[\mathrm{t2}\left[1\right]\,\mathrm{t2}\left[2\right]\,\mathrm{t2}\left[4\right]\right]}_{}\,\mathrm{datasetlabels}\=\left[''One\; Thread''\,''Two\; Threads''\,''Four\; Threads''\right]\,\mathrm{labels}\=\left[''''\,''Seconds''\right]\,\mathrm{gridlines}\right)$