1e2cf2bc45
Sometimes it is useful to disable a trace event. Removing the event from trace-events is not enough since source code will call the trace_*() function for the event. This patch makes it easy to build without specific trace events by marking them disabled in trace-events: disable multiwrite_cb(void *mcb, int ret) "mcb %p ret %d" This builds without the multiwrite_cb trace event. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> trace: Allow bulk enabling/disabling of trace events at compile time For 'simple' trace backend, allow bulk enabling/disabling of trace events at compile time. Trace events that are preceded by 'disable' keyword are compiled in, but turned off by default. These can individually be turned on using the monitor. All other trace events are enabled by default. TODO : This could be enhanced when the trace-event namespace is partitioned into a group and an ID within that group. In such a case, marking a group as enabled would automatically enable all trace-events listed under it. Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
30 lines
1.0 KiB
Plaintext
30 lines
1.0 KiB
Plaintext
# Trace events for debugging and performance instrumentation
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#
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# This file is processed by the tracetool script during the build.
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#
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# To add a new trace event:
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#
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# 1. Choose a name for the trace event. Declare its arguments and format
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# string.
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#
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# 2. Call the trace event from code using trace_##name, e.g. multiwrite_cb() ->
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# trace_multiwrite_cb(). The source file must #include "trace.h".
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#
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# Format of a trace event:
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#
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# [disable] <name>(<type1> <arg1>[, <type2> <arg2>] ...) "<format-string>"
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#
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# Example: qemu_malloc(size_t size) "size %zu"
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#
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# The "disable" keyword will build without the trace event.
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# In case of 'simple' trace backend, it will allow the trace event to be
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# compiled, but this would be turned off by default. It can be toggled on via
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# the monitor.
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#
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# The <name> must be a valid as a C function name.
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#
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# Types should be standard C types. Use void * for pointers because the trace
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# system may not have the necessary headers included.
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#
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# The <format-string> should be a sprintf()-compatible format string.
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