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2011-03-07simpletrace: Thread-safe tracingStefan Hajnoczi
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>
2010-10-23qemu-timer: move commonly used timer code to qemu-timer-commonBlue Swirl
Move timer init functions to a new file, qemu-timer-common.c. Make other critical timer functions inlined to preserve performance in qemu-timer.c, also move muldiv64() (used by the inline functions) to qemu-timer.h. Adjust block/raw-posix.c and simpletrace.c to use get_clock() directly. Remove a similar/duplicate definition in qemu-tool.c. Adjust hw/omap_clk.c to include qemu-timer.h because muldiv64() is used there. After this change, tracing can be used also for user code and simpletrace on Win32. Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Acked-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-10-20trace: improve info trace outputBlue Swirl
Use PRI*64 to print full 64 bit data even on ILP32 hosts. Print also sixth tracepoint parameter. Acked-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-10-13trace: print a warning if user tries to enable an unknown trace eventBlue Swirl
There was no warning if a bad trace event name was given to 'trace-event' command, thus the user could think that the command was successful even if this was not the case. Print a warning if the user tries to enable a trace event which is not known. Acked-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-09-09trace: Add trace-file command to open/close/flush trace fileStefan Hajnoczi
This patch adds the trace-file command: trace-file [on|off|flush] Open, close, or flush the trace file. If no argument is given, the status of the trace file is displayed. The trace file is turned on by default but is only written out when the trace buffer becomes full. The flush operation can be used to force write out at any time. Turning off the trace file does not change the state of trace events; tracing will continue to the trace buffer. When the trace file is off, use "info trace" to display the contents of the trace buffer in memory. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> This commit also contains the trace-file sub-command from the following commit: commit 5ce8d1a957afae2c52ad748944ce72848ccf57bd Author: Prerna Saxena <prerna@linux.vnet.ibm.com> Date: Wed Aug 4 16:23:54 2010 +0530 trace: Add options to specify trace file name at startup and runtime This patch adds an optional command line switch '-trace' to specify the filename to write traces to, when qemu starts. Eg, If compiled with the 'simple' trace backend, [temp@system]$ qemu -trace FILENAME IMAGE Allows the binary traces to be written to FILENAME instead of the option set at config-time. Also, this adds monitor sub-command 'set' to trace-file commands to dynamically change trace log file at runtime. Eg, (qemu)trace-file set FILENAME This allows one to set trace outputs to FILENAME from the default specified at startup. Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2010-09-09trace: Specify trace file namePrerna Saxena
Allow users to specify a file for trace-outputs at configuration. Also, allow trace files to be annotated by <pid> so each qemu instance has unique traces. The trace file name can be passed as a config option: --trace-file=/path/to/file (Default: trace ) At runtime, the pid of the qemu process is appended to the filename so that mutiple qemu instances do not have overlapping logs. Eg : trace-1234 for qemu launched with pid 1234. I have yet to test this on windows. getpid() is used at many places in code(including vnc.c), so I'm hoping this would be okay too. Edited-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2010-09-09trace: Support for dynamically enabling/disabling trace eventsPrerna Saxena
This patch adds support for dynamically enabling/disabling of trace events. This is done by internally maintaining each trace event's state, and permitting logging of data from a trace event only if it is in an 'active' state. Monitor commands added : 1) info trace-events : to view all available trace events and their state. 2) trace-event NAME on|off : to enable/disable data logging from a given trace event. Eg, trace-event paio_submit off disables logging of data when paio_submit is hit. By default, all trace-events are disabled. One can enable desired trace-events via the monitor. Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> trace: Monitor command 'info trace' Monitor command 'info trace' to display contents of trace buffer Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> trace: Remove monitor.h dependency from simpletrace User-mode targets don't have a monitor so the simple trace backend currently does not build on those targets. This patch abstracts the monitor printing interface so there is no direct coupling between simpletrace and the monitor. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2010-09-09trace: Add simple built-in tracing backendStefan Hajnoczi
This patch adds a simple tracer which produces binary trace files. To try out the simple backend: $ ./configure --trace-backend=simple $ make After running QEMU you can pretty-print the trace: $ ./simpletrace.py trace-events trace.log The output of simpletrace.py looks like this: qemu_realloc 0.699 ptr=0x24363f0 size=0x3 newptr=0x24363f0 qemu_free 0.768 ptr=0x24363f0 ^ ^---- timestamp delta (us) |____ trace event name Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> trace: Make trace record fields 64-bit Explicitly use 64-bit fields in trace records so that timestamps and magic numbers work for 32-bit host builds. Includes fixes from Prerna Saxena <prerna@linux.vnet.ibm.com>. Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>