Trace events outside the global mutex cannot be used with the simple
trace backend since it is not thread-safe. There is no check to prevent
them being enabled so people sometimes learn this the hard way.
This patch restructures the simple trace backend with a ring buffer
suitable for multiple concurrent writers. A writeout thread empties the
trace buffer when threshold fill levels are reached. Should the
writeout thread be unable to keep up with trace generation, records will
simply be dropped.
Each time events are dropped a special record is written to the trace
file indicating how many events were dropped. The event ID is
0xfffffffffffffffe and its signature is dropped(uint32_t count).
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Optional feature allowing a user to generate the probe list to match
the name of the binary, in case they wish to install qemu under a
different name than qemu-{system,user},<arch>
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Stefan Hajnoczi <stefaha@linux.vnet.ibm.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
The simpletrace.py script pretty-prints a binary trace file. Most of
the code can be reused by trace file analysis scripts, so turn it into a
module.
Here is an example script that uses the new simpletrace module:
#!/usr/bin/env python
# Print virtqueue elements that were never returned to the guest.
import simpletrace
class VirtqueueRequestTracker(simpletrace.Analyzer):
def __init__(self):
self.elems = set()
def virtqueue_pop(self, vq, elem, in_num, out_num):
self.elems.add(elem)
def virtqueue_fill(self, vq, elem, length, idx):
self.elems.remove(elem)
def end(self):
for elem in self.elems:
print hex(elem)
simpletrace.run(VirtqueueRequestTracker())
The simpletrace API is based around the Analyzer class. Users implement
an analyzer subclass and add methods for trace events they want to
process. A catchall() method is invoked for trace events which do not
have dedicated methods. Finally, there are also begin() and end()
methods like in sed that can be used to perform setup or print
statistics at the end.
A binary trace file is processed either with:
simpletrace.run(analyzer) # uses command-line args
or with:
simpletrace.process('path/to/trace-events',
'path/to/trace-file',
analyzer)
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This backend sends trace events to standard error output during the emulation.
Also add a "--list-backends" option to tracetool, so configure script can
display the list of available backends.
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Acked-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Include a header to get the declaration for xml_builtin. This
avoids a warning from sparse:
CC m68k-softmmu/gdbstub-xml.o
gdbstub-xml.c:244:12: warning: symbol 'xml_builtin' was not declared. Should it be static?
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Change checkpatch.pl for QEMU use:
- Root directory detection
- Forbid tabs
- Indent at 4 spaces
- Allow typedefs
- Enforce brace use even for single statement blocks
- Don't suggest nonexistent cleanup tools
Mention the script in CODING_STYLE.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
