Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Mon, 16 Jan 2006 23:54:49 +0100

On Monday 16 January 2006 20:17, Andrew Johnson wrote:
> liushu wrote:
> >    I need vxStats for Epics3.13.8.Where can I get it?
>
> Are you aware that there is a version of vxStats already included in
> Base R3.13.8?  It was unbundled for the R3.14.x series, but is usable
> in the earlier versions as is.

Note that this version of vxStats calls memPartInfoGet() which is well 
known to (at least in VxWorks 5.2 and 5.4.3 (tornado 2.0.2)) contain a 
serious bug that might corrupt the heap free list and cause 
intermittent IOC crashes. This happens the more frequently, the more 
the IOC allocates/deallocates memory at runtime. Particularly, the 3.13 
base version of vxStats should not be combined with using a vxi-11 
driver based on VxWorks RPC implementation (i.e. the 3.13. GPIB 
driver).

I have a simple test routine that randomly allocates and deallocates 
memory blocks of different sizes. Running this in a task on an IOC 
together with a periodically scanned memory statistics record reliably 
crashes the IOC after a short time (less than a minute, IIRC).

The easiest fix is to replace all calls to memPartInfoGet() with direct 
accesses to the members of the MEM_PART structure (which of course must 
be mutex guarded using the semaphore that is also part of this 
structure). It seems that the statistics data in there are 
automatically kept up-to-date, at least in VxWorks 5.4.3. I have 
recently created a patched version of the 3.13.9 version of vxStats 
that I can make available for download if people are interested.

See also: http://www.xs4all.nl/~borkhuis/vxworks/vxw_pt5.html#5.4A

Ben

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System