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[Qemu-devel] [PULL 2/7] trace: avoid SystemTap dtrace(1) warnings on empty files

Stefan Hajnoczi posted 7 patches 6 years, 10 months ago
Maintainers: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Aurelien Jarno <aurelien@aurel32.net>, Anthony Perard <anthony.perard@citrix.com>, Greg Kurz <groug@kaod.org>, Alex Williamson <alex.williamson@redhat.com>, John Snow <jsnow@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Riku Voipio <riku.voipio@iki.fi>, Fam Zheng <fam@euphon.net>, Juan Quintela <quintela@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Laurent Vivier <laurent@vivier.eu>, David Hildenbrand <david@redhat.com>, Aleksandar Markovic <amarkovic@wavecomp.com>, Stefano Stabellini <sstabellini@kernel.org>, Igor Mammedov <imammedo@redhat.com>, Markus Armbruster <armbru@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, David Gibson <david@gibson.dropbear.id.au>, Gerd Hoffmann <kraxel@redhat.com>, Halil Pasic <pasic@linux.ibm.com>, Eric Blake <eblake@redhat.com>, Stefan Berger <stefanb@linux.ibm.com>, Cornelia Huck <cohuck@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>, Richard Henderson <rth@twiddle.net>, Kevin Wolf <kwolf@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Jason Wang <jasowang@redhat.com>, Aleksandar Rikalo <arikalo@wavecomp.com>, "Andreas Färber" <afaerber@suse.de>, Paul Durrant <paul.durrant@citrix.com>, Michael Roth <mdroth@linux.vnet.ibm.com>, Stefan Hajnoczi <stefanha@redhat.com>, Helge Deller <deller@gmx.de>, Max Reitz <mreitz@redhat.com>, Artyom Tarasenko <atar4qemu@gmail.com>, Yuval Shaia <yuval.shaia@oracle.com>
There is a newer version of this series
[Qemu-devel] [PULL 2/7] trace: avoid SystemTap dtrace(1) warnings on empty files
Posted by Stefan Hajnoczi 6 years, 10 months ago 
target/hppa/trace-events only contains disabled events, resulting in a
trace-dtrace.dtrace file that says "provider qemu {}".  SystemTap's
dtrace(1) tool prints a warning when processing this input file.

This patch avoids the error by emitting an empty file instead of
"provider qemu {}" when there are no enabled trace events.

Fixes: 23c3d569f44284066714ff7c46bc4f19e630583f ("target/hppa: add TLB trace events")
Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Message-id: 20190321170831.6539-3-stefanha@redhat.com
Message-Id: <20190321170831.6539-3-stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 scripts/tracetool/format/d.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scripts/tracetool/format/d.py b/scripts/tracetool/format/d.py
index 78397c24d2..c7cb2a93a6 100644
--- a/scripts/tracetool/format/d.py
+++ b/scripts/tracetool/format/d.py
@@ -33,6 +33,11 @@ def generate(events, backend, group):
     events = [e for e in events
               if "disable" not in e.properties]
 
+    # SystemTap's dtrace(1) warns about empty "provider qemu {}" but is happy
+    # with an empty file.  Avoid the warning.
+    if not events:
+        return
+
     out('/* This file is autogenerated by tracetool, do not edit. */'
         '',
         'provider qemu {')
-- 
2.20.1

Patchew 2.1-devel-b67e4c2

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