Conference turris::pca

948.0. "DYNAMIC ACTIVATION OF PCA$COLLECTOR" by TAV02::MILCHIN () Wed May 14 1997 06:25

	HI!

	One of my customers (which extensively uses PCA descovering ADA aplications
performance bottlenecks) found that he can dynamically activate the PCA
COLLECTOR using a same technique as dynamic activation of the DEBUGGER: I.E-
Siganalign SS$_DEBUG through LIB$SIGNAL. He uses this technique in order to
skip the ADA elaboration code and start the performance data collection from
his actual application code. The problem is that this technique works on 
OPENVMS VAX, but does not work on OPENVMS ALPHA (tested using PCA V4.4-3 and
T4.5-3). It seems that PCA$COLLECTOR does not pass its initialization code when
activated in the above way on ALPHA. It does not execute its initialization 
procedure pointed by PCAC$INIT logical name and does not stop at PCA> prompt.
It only displays the 'PCA COLLECTOR VERSION ...' message and then then the application 
continues its execution and silently terminates with the %PCA-I-NODATACOL,...
message. I know that this dynamic activation of PCA$COLLECTOR is not documented,
however, it seems me as an elegand solution to start PCA collection at 
appropriate point of execution (the PCA collector ability to set breakpoints
remained in the wishlist since a couple of years, as I know).
	My question is: Will the dynamic activation of PCA collector, as described
above, be possible on ALPHA?
	Thanks in advance.
		MICHAEL

    Hi Michael,
    
    This is very interesting; thanks for reporting it. I've raised this as
    PCA wish #33.
    
    It will take some research to determine why this doesn't work on an
    Alpha; we hope to undertake this at some point after DECset V12.2 is
    released in order to understand what's going on. We can't promise
    anything, but it's on the wishlist now.
    
    -- Daryl

	DARYL!

	Thank you for your quick reply. For the time being I suggested a 
work-arround for the customers problem. He wants to skip the data collection 
for ADA elaboration code because of significant part of data is tied to this
ADA$ELAB_xxx routine. I suggested him to create a filter for those data points 
or to ploat the data using /NOMAIN_IMAGE.
	Regards!
		MICHAEL

    Hi Michael,
    
    I haven't had much experience using PCA with Ada, but your suggested
    workarounds sound reasonable to me. If the customer would like other
    suggestions, we might be able to offer some additional help if more
    details were posted about their program and the kinds of analysis they
    wish to perform.
    
    -- Daryl