From patchwork Mon Aug 9 14:03:28 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: trace: Documentation update Date: Mon, 09 Aug 2010 04:03:28 -0000 From: Stefan Hajnoczi X-Patchwork-Id: 61281 Message-Id: <1281362608-10106-1-git-send-email-stefanha@linux.vnet.ibm.com> To: Cc: Stefan Hajnoczi , Prerna Saxena Signed-off-by: Stefan Hajnoczi --- docs/tracing.txt | 21 ++++++++++++--------- 1 files changed, 12 insertions(+), 9 deletions(-) diff --git a/docs/tracing.txt b/docs/tracing.txt index abbae6b..fe3c6ac 100644 --- a/docs/tracing.txt +++ b/docs/tracing.txt @@ -18,7 +18,7 @@ for debugging, profiling, and observing execution. 3. Pretty-print the binary trace file: - ./simpletrace.py trace-events /tmp/trace.log + ./simpletrace.py trace-events /tmp/trace-* == Trace events == @@ -70,11 +70,11 @@ trace events. == Trace backends == -The tracetool script not only automates tedious trace event code generation, -it also keeps the trace event declarations independent of the trace backend. -The trace events are not tightly coupled to a specific trace backend, such as -LTTng or SystemTap. Support for trace backends can be added by extending the -tracetool script. +The tracetool script automates tedious trace event code generation and also +keeps the trace event declarations independent of the trace backend. The trace +events are not tightly coupled to a specific trace backend, such as LTTng or +SystemTap. Support for trace backends can be added by extending the tracetool +script. The trace backend is chosen at configure time and only one trace backend can be built into the binary: @@ -116,16 +116,19 @@ unless you have specific needs for more advanced backends. * trace-event NAME on|off Enable/disable a given trace event. +* trace-file on|off|flush|set + Enable/disable/flush the trace file or set the trace file name. + ==== Enabling/disabling trace events programmatically ==== -The change_trace_event_state() function can be used to enable or disable trace +The st_change_trace_event_state() function can be used to enable or disable trace events at runtime inside QEMU: #include "trace.h" - change_trace_event_state("virtio_irq", true); /* enable */ + st_change_trace_event_state("virtio_irq", true); /* enable */ [...] - change_trace_event_state("virtio_irq", false); /* disable */ + st_change_trace_event_state("virtio_irq", false); /* disable */ ==== Analyzing trace files ====