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Diffstat (limited to 'docs/tracing.txt')
| -rw-r--r-- | docs/tracing.txt | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/docs/tracing.txt b/docs/tracing.txt index bfc261bcaf..bf2e15ce30 100644 --- a/docs/tracing.txt +++ b/docs/tracing.txt @@ -214,6 +214,42 @@ The "ust" backend uses the LTTng Userspace Tracer library. There are no monitor commands built into QEMU, instead UST utilities should be used to list, enable/disable, and dump traces. +Package lttng-tools is required for userspace tracing. You must ensure that the +current user belongs to the "tracing" group, or manually launch the +lttng-sessiond daemon for the current user prior to running any instance of +QEMU. + +While running an instrumented QEMU, LTTng should be able to list all available +events: + + lttng list -u + +Create tracing session: + + lttng create mysession + +Enable events: + + lttng enable-event qemu:g_malloc -u + +Where the events can either be a comma-separated list of events, or "-a" to +enable all tracepoint events. Start and stop tracing as needed: + + lttng start + lttng stop + +View the trace: + + lttng view + +Destroy tracing session: + + lttng destroy + +Babeltrace can be used at any later time to view the trace: + + babeltrace $HOME/lttng-traces/mysession-<date>-<time> + === SystemTap === The "dtrace" backend uses DTrace sdt probes but has only been tested with |