IntelĀ® Trace Collector 9.1 Update 2 User and Reference Guide
MEM-MAXBLOCKS <maximum number of blocks>
VT_MEM_MAXBLOCKS
4096
Intel Trace Collector does not allocate more than this number of blocks in main memory. If the maximum number of blocks is filled or allocating new blocks fails, Intel Trace Collector either flushes some of them onto disk (AUTOFLUSH), or overwrites the oldest blocks (MEM-OVERWRITE) or stops recording further trace data.