On 01/06/2017 09:55 AM, Daniel P. Berrange wrote: > Describe use of per-subdir trace events files and how it impacts > code generation. > > Signed-off-by: Daniel P. Berrange <berra...@redhat.com> > --- > docs/tracing.txt | 61 > +++++++++++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 52 insertions(+), 9 deletions(-) > > diff --git a/docs/tracing.txt b/docs/tracing.txt > index f351998a..3262a61 100644 > --- a/docs/tracing.txt > +++ b/docs/tracing.txt > @@ -27,18 +27,51 @@ for debugging, profiling, and observing execution. > > == Trace events == > > +=== Sub-directory setup === > + > Each directory in the source tree can declare a set of static trace events > -in a "trace-events" file. Each trace event declaration names the event, its > -arguments, and the format string which can be used for pretty-printing: > +in a "trace-events" file. The first (non-comment) statement in the file > +must be "@id_offset(NN)" where NN is an integer that is unique among all > +"trace-events" files in the QEMU source tree. The IDs can be arbitrarily > +chosen, but for extra fun the current "trace-events" files use values from > +the "powerful number" integer sequence :-)
Is this true? I don't see an @id_offset() comment in any of your earlier patches, or in the unpatched tree. > +In the sub-directory the following files will be automatically generated > + > + - trace.c - the trace event state declarations > + - trace.h - the trace event enums and probe functions > + - trace-dtrace.h - DTrace speci s/speci/specification/ ? > + - trace-dtrace.dtrace - DTrace event probe helper declaration > + - trace-dtrace.o - binary DTrace provider (generated by dtrace) > + - trace-ust.h - UST event probe helper declarations > + > +Source files in the sub-directory should only #include the 'trace.h' > +file and use the full sub-directory path. eg io/channel-buffer.c > +would do > > -All "trace-events" files must be listed in the "trace-event-y" make variable > -in the top level Makefile.objs. During build the individual files are > combined > -to create a "trace-events-all" file, which is processed by the "tracetool" > -script during build to generate code for the trace events. The > -"trace-events-all" file is also installed into "/usr/share/qemu". > + #include "io/trace.h" > + > +While it is permited to include a trace.h file from outside a source s/permited/permitted/ > +files' own sub-directory, this is discouraged in general. It is strongly > +preferred that all events be declared directly in the sub-directory that > +uses them. > + > +=== Using trace events === > -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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