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RE: question regarding accessing a target variable
- From: "Kai Wong" <kai_wong at symantec dot com>
- To: <systemtap at sources dot redhat dot com>
- Cc: "Frank Ch. Eigler" <fche at redhat dot com>
- Date: Fri, 2 Jan 2009 18:28:59 -0700
- Subject: RE: question regarding accessing a target variable
- References: <20217654.post@talk.nabble.com> <y0mtzawurrj.fsf@ton.toronto.redhat.com> <1A193CCB5218B14589B1979BC7D510E006F0EB1E@TUS1XCHCLUPIN11.enterprise.veritas.com> <20081029201826.GC16968@redhat.com> <1A193CCB5218B14589B1979BC7D510E006F0ECBC@TUS1XCHCLUPIN11.enterprise.veritas.com> <1A193CCB5218B14589B1979BC7D510E007077719@TUS1XCHCLUPIN11.enterprise.veritas.com> <20081104152629.GB28139@redhat.com> <1A193CCB5218B14589B1979BC7D510E0070F51F0@TUS1XCHCLUPIN12.enterprise.veritas.com> <20081107020842.GG20928@redhat.com>
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