Bug 7043 - Support unified trace buffer
Summary: Support unified trace buffer
Status: RESOLVED WORKSFORME
Alias: None
Product: systemtap
Classification: Unclassified
Component: runtime (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: David Smith
URL:
Keywords:
: 9801 (view as bug list)
Depends on:
Blocks: 7042
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Reported: 2008-11-21 13:31 UTC by Masami Hiramatsu
Modified: 2011-05-17 10:38 UTC (History)
2 users (show)

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Description Masami Hiramatsu 2008-11-21 13:31:06 UTC 
Support unified trace buffer instead of relayfs, since relay will be replaced by it.

see kernel/trace/ring_buffer.c.
Comment 1 Masami Hiramatsu 2008-12-23 22:43:25 UTC 
I think there might be another plan that stap generates ftrace-plug-in tracer
instead of using ring-buffer directly.
Comment 2 Frank Ch. Eigler 2009-01-29 16:36:54 UTC 
*** Bug 9801 has been marked as a duplicate of this bug. ***
Comment 3 Frank Ch. Eigler 2009-01-29 22:55:09 UTC 
Let's assess whether the ring buffer widget, or the larger control
structures around it in ftrace, are relevant/useful to systemtap.

We need at least:
- access to the ftrace buffering stuff from modules
- the ring buffers need to contain formatted ascii, since that is what scripts
  produce, and not rely on subsequent trace_iter printing like current ftrace
  engines; maybe reuse ftrace_printk
- per-script trace files (instead of /debugfs/tracing/trace intermingled) ...
  unless some goofy multiplexing is the only way
- probably no connection with the overall control switch
  /tracing/tracing_enabled), since scripts come and go at any time
Comment 4 Frank Ch. Eigler 2011-05-17 10:38:30 UTC 
-DSTP_USE_RING_BUFFER does this.