user/sven/linux.git/kernel/trace/trace_entries.h, branch v4.9.119

tracing: Add NMI tracing in hwlat detector

2016-09-02T16:47:55Z

As NMIs can also cause latency when interrupts are disabled, the hwlat detectory has no way to know if the latency it detects is from an NMI or an SMI or some other hardware glitch. As ftrace_nmi_enter/exit() funtions are no longer used (except for sh, which isn't supported anymore), I converted those to "arch_ftrace_nmi_enter/exit" and use ftrace_nmi_enter/exit() to check if hwlat detector is tracing or not, and if so, it calls into the hwlat utility. Since the hwlat detector only has a single kthread that is spinning with interrupts disabled, it marks what CPU it is on, and if the NMI callback happens on that CPU, it records the time spent in that NMI. This is added to the output that is generated by the hwlat detector as: #3 inner/outer(us): 9/9 ts:1470836488.206734548 #4 inner/outer(us): 0/8 ts:1470836497.140808588 #5 inner/outer(us): 0/6 ts:1470836499.140825168 nmi-total:5 nmi-count:1 #6 inner/outer(us): 9/9 ts:1470836501.140841748 All time is still tracked in microseconds. The NMI information is only shown when an NMI occurred during the sample. Signed-off-by: Steven Rostedt

tracing: Added hardware latency tracer

2016-09-02T16:47:51Z

The hardware latency tracer has been in the PREEMPT_RT patch for some time. It is used to detect possible SMIs or any other hardware interruptions that the kernel is unaware of. Note, NMIs may also be detected, but that may be good to note as well. The logic is pretty simple. It simply creates a thread that spins on a single CPU for a specified amount of time (width) within a periodic window (window). These numbers may be adjusted by their cooresponding names in /sys/kernel/tracing/hwlat_detector/ The defaults are window = 1000000 us (1 second) width = 500000 us (1/2 second) The loop consists of: t1 = trace_clock_local(); t2 = trace_clock_local(); Where trace_clock_local() is a variant of sched_clock(). The difference of t2 - t1 is recorded as the "inner" timestamp and also the timestamp t1 - prev_t2 is recorded as the "outer" timestamp. If either of these differences are greater than the time denoted in /sys/kernel/tracing/tracing_thresh then it records the event. When this tracer is started, and tracing_thresh is zero, it changes to the default threshold of 10 us. The hwlat tracer in the PREEMPT_RT patch was originally written by Jon Masters. I have modified it quite a bit and turned it into a tracer. Based-on-code-by: Jon Masters Signed-off-by: Steven Rostedt

ftrace: Reduce size of function graph entries

2016-07-05T21:28:30Z

Currently ftrace_graph_ent{,_entry} and ftrace_graph_ret{,_entry} struct can have padding bytes at the end due to alignment in 64-bit data type. As these data are recorded so frequently, those paddings waste non-negligible space. As the ring buffer maintains alignment properly for each architecture, just to remove the extra padding using 'packed' attribute. ftrace_graph_ent_entry: 24 -> 20 ftrace_graph_ret_entry: 48 -> 44 Also I moved the 'overrun' field in struct ftrace_graph_ret to minimize the padding in the middle. Tested on x86_64 only. Link: http://lkml.kernel.org/r/1467197808-13578-1-git-send-email-namhyung@kernel.org Cc: Ingo Molnar Cc: linux-arch@vger.kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt

tracing: %pF is only for function pointers

2015-03-25T12:57:22Z

Use %pS for actual addresses, otherwise you'll get bad output on arches like ppc64 where %pF expects a function descriptor. Link: http://lkml.kernel.org/r/1426130037-17956-22-git-send-email-scottwood@freescale.com Signed-off-by: Scott Wood Signed-off-by: Steven Rostedt

tracing: Add trace_puts() for even faster trace_printk() tracing

2013-03-15T04:35:55Z

The trace_printk() is extremely fast and is very handy as it can be used in any context (including NMIs!). But it still requires scanning the fmt string for parsing the args. Even the trace_bprintk() requires a scan to know what args will be saved, although it doesn't copy the format string itself. Several times trace_printk() has no args, and wastes cpu cycles scanning the fmt string. Adding trace_puts() allows the developer to use an even faster tracing method that only saves the pointer to the string in the ring buffer without doing any format parsing at all. This will help remove even more of the "Heisenbug" effect, when debugging. Also fixed up the F_printk()s for the ftrace internal bprint and print events. Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Frederic Weisbecker Signed-off-by: Steven Rostedt

Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent

2012-03-24T07:19:09Z

tracing: Fix ftrace stack trace entries

2012-03-22T16:19:23Z

8 hex characters tell only half the tale for 64 bit CPUs, so use the appropriate length. Link: http://lkml.kernel.org/r/1332411501-8059-2-git-send-email-wolfgang.mauerer@siemens.com Cc: stable@vger.kernel.org Signed-off-by: Wolfgang Mauerer Signed-off-by: Steven Rostedt

ftrace: Allow to specify filter field type for ftrace events

2012-02-21T16:08:29Z

Adding FILTER_TRACE_FN event field type for function tracepoint event, so it can be properly recognized within filtering code. Currently all fields of ftrace subsystem events share the common field type FILTER_OTHER. Since the function trace fields need special care within the filtering code we need to recognize it properly, hence adding the FILTER_TRACE_FN event type. Adding filter parameter to the FTRACE_ENTRY macro, to specify the filter field type for the event. Link: http://lkml.kernel.org/r/1329317514-8131-7-git-send-email-jolsa@redhat.com Signed-off-by: Jiri Olsa Signed-off-by: Steven Rostedt

ftrace, perf: Add support to use function tracepoint in perf

2012-02-21T16:08:27Z

Adding perf registration support for the ftrace function event, so it is now possible to register it via perf interface. The perf_event struct statically contains ftrace_ops as a handle for function tracer. The function tracer is registered/unregistered in open/close actions. To be efficient, we enable/disable ftrace_ops each time the traced process is scheduled in/out (via TRACE_REG_PERF_(ADD|DELL) handlers). This way tracing is enabled only when the process is running. Intentionally using this way instead of the event's hw state PERF_HES_STOPPED, which would not disable the ftrace_ops. It is now possible to use function trace within perf commands like: perf record -e ftrace:function ls perf stat -e ftrace:function ls Allowed only for root. Link: http://lkml.kernel.org/r/1329317514-8131-6-git-send-email-jolsa@redhat.com Acked-by: Frederic Weisbecker Signed-off-by: Jiri Olsa Signed-off-by: Steven Rostedt

tracing: Have dynamic size event stack traces

2011-07-14T20:36:53Z

Currently the stack trace per event in ftace is only 8 frames. This can be quite limiting and sometimes useless. Especially when the "ignore frames" is wrong and we also use up stack frames for the event processing itself. Change this to be dynamic by adding a percpu buffer that we can write a large stack frame into and then copy into the ring buffer. For interrupts and NMIs that come in while another event is being process, will only get to use the 8 frame stack. That should be enough as the task that it interrupted will have the full stack frame anyway. Requested-by: Thomas Gleixner Signed-off-by: Steven Rostedt