Home page: http://www.crystalballinc.com/vlad/software/
VTmalloc is a replacement memory allocator for Tcl which tries hard to reduce memory consumption while also remaining fast and free of lock contention. These characteristics are important for long-lived servers such as NaviServer which, after long periods of continuous use, can fragment the memory space which leads to an ever increasing memory footprint.
a fast Tcl memory allocator to use when Tcl is compiled for threads (--enable-threads). The allocator is tuned for speed and low overall memory consumption, as it returns the memory to the system on each thread exit or when instructed by the programmer.
Simply replace the generic/tclThreadAlloc.c file from the Tcl distribution, then re-compile and re-install the Tcl library.
Performance test results: http://naviserver.cvs.sourceforge.net/naviserver/vtmalloc/README?view=markup