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* [Bug translator/10796] New: thread-specific globals
@ 2009-10-16 22:23 jistone at redhat dot com
  2009-10-23 23:42 ` [Bug translator/10796] " jistone at redhat dot com
  2009-10-26 16:03 ` jkenisto at us dot ibm dot com
  0 siblings, 2 replies; 3+ messages in thread
From: jistone at redhat dot com @ 2009-10-16 22:23 UTC (permalink / raw)
  To: systemtap

Similar to PR10795, it would also be nice to have native per-thread globals. 
It's a common pattern to have maps indexed only by tid(), so it would be nice if
that were automatic and lockless.

Per-thread is not as easy as per-cpu though -- we'll probably need to have a
fixed pool of thread storage areas, allocating when a probe hits a thread,
deallocating when a thread dies (perhaps even on exec).  Those lookups might
need some locking, but hopefully that could be more fine-grained than wrapping
the entire probe.

-- 
           Summary: thread-specific globals
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: translator
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: jistone at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=10796

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* [Bug translator/10796] thread-specific globals
  2009-10-16 22:23 [Bug translator/10796] New: thread-specific globals jistone at redhat dot com
@ 2009-10-23 23:42 ` jistone at redhat dot com
  2009-10-26 16:03 ` jkenisto at us dot ibm dot com
  1 sibling, 0 replies; 3+ messages in thread
From: jistone at redhat dot com @ 2009-10-23 23:42 UTC (permalink / raw)
  To: systemtap


------- Additional Comments From jistone at redhat dot com  2009-10-23 23:42 -------
If we get this such that it performs better than plain "array[tid()]"
mechanisms, then we should port the .return $target saving to use this feature.

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=10796

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* [Bug translator/10796] thread-specific globals
  2009-10-16 22:23 [Bug translator/10796] New: thread-specific globals jistone at redhat dot com
  2009-10-23 23:42 ` [Bug translator/10796] " jistone at redhat dot com
@ 2009-10-26 16:03 ` jkenisto at us dot ibm dot com
  1 sibling, 0 replies; 3+ messages in thread
From: jkenisto at us dot ibm dot com @ 2009-10-26 16:03 UTC (permalink / raw)
  To: systemtap


------- Additional Comments From jkenisto at us dot ibm dot com  2009-10-26 16:02 -------
(In reply to comment #1)
> If we get this such that it performs better than plain "array[tid()]"
> mechanisms, then we should port the .return $target saving to use this feature.

If you're going to revise that feature, consider using
kretprobe_instance->data[] to store such data between call and return.  That's
what it was designed for.  See PR #5916 and section 1.3.2 of
Documentation/kprobes.txt.



-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=10796

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end of thread, other threads:[~2009-10-26 16:03 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2009-10-16 22:23 [Bug translator/10796] New: thread-specific globals jistone at redhat dot com
2009-10-23 23:42 ` [Bug translator/10796] " jistone at redhat dot com
2009-10-26 16:03 ` jkenisto at us dot ibm dot com

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