The sched provider defines the stable "lgrp" variable that is the lgroup of
the current CPU. This is mostly interesting when we can compare it with the
actual thread home lgroup, so I'd like to extend the lwpsinfo_t structure with
the new pr_lgrp field which will be implemented using translator. This will
match the addition of the pr_lgrp field to the proc(4) lwpsinfo_t structure
that is done with the NUMA observability changes (it utilises one of the five
reserved fields).
The pr_lgrp field will only be available for consumers with dtrace_kernel
privilege since the translator needs to do kernel pointer dereference.
This change allows simple script to get lgroup migration statistics, e.g.
sched:::on-cpu
/execname != "sched" && curlwpsinfo->pr_lgrp != lgrp/
{
@[execname, curlwpsinfo->pr_lgrp] = count();
}
snmpd 3 1
utmpd 1 1
automountd 2 2
intrd 2 3
dtrace 2 4
fmd 1 12
I have a few questions related to this proposed change:
- Are there any objections to this change?
- Are there any stability levels associated with specific fields of lwpsinfo_t
for DTrace consumers?
- What parts of the documentation are affected by this change other than the
DTrace guide?
- Is there any embedded DTrace knowledge of lwpsinfo_t fields other than in
sched.d?
__
Alex Kolbasov
http://blogs.sun.com/akolb
