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RE: question regarding accessing a target variable


FChE wrote:
> I jotted some melancholy notes on this in the wiki.
> http://sources.redhat.com/systemtap/wiki/TipContextVariables

If none of the other options applies or works, but I can modify the
source of the probed software, does
inserting inline-assembly directives as shown in that example slow down
the performance of the probed software when not probed (assuming the
"volatile" directives stays)?

-Kai

-----Original Message-----
From: Kai Wong 
Sent: Friday, January 02, 2009 2:29 PM
To: 'systemtap@sources.redhat.com'
Cc: 'Frank Ch. Eigler'
Subject: question regarding accessing a target variable

Hi,

I try to access a target variable (e.g., block, which is a c local
variable within a probed function), but no matter what line number I
place the probe within the function (e.g., probe
module("vxglm").statement("vxg_recv_block_grant@/home2/kwong/glm-bld/50m
p3_clustrace/kernel/glm/smp/glmbpxy.c:67")), I get the following
message:

semantic error: not accessible at this address: identifier '$block' at
/usr/share/systemtap/tapset/glm/msgsup.stp:20:123

that target variable was actually assigned a valid value and referenced
in many different lines within the probed function. I have no trouble
with other target variables that are c local variables.

What can I do to make a c local variable more accessible to systemtap as
a target variable?

Kai 


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