user/sven/linux.git/kernel/trace/trace_hwlat.c, branch v5.3.14

tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency

2019-10-17T20:47:31Z

commit fc64e4ad80d4b72efce116f87b3174f0b7196f8e upstream. max_latency is intended to record the maximum ever observed hardware latency, which may occur in either part of the loop (inner/outer). So we need to also consider the outer-loop sample when updating max_latency. Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu Fixes: e7c15cd8a113 ("tracing: Added hardware latency tracer") Cc: stable@vger.kernel.org Signed-off-by: Srivatsa S. Bhat (VMware) Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing/hwlat: Report total time spent in all NMIs during the sample

2019-10-17T20:47:30Z

commit 98dc19c11470ee6048aba723d77079ad2cda8a52 upstream. nmi_total_ts is supposed to record the total time spent in *all* NMIs that occur on the given CPU during the (active portion of the) sampling window. However, the code seems to be overwriting this variable for each NMI, thereby only recording the time spent in the most recent NMI. Fix it by accumulating the duration instead. Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu Fixes: 7b2c86250122 ("tracing: Add NMI tracing in hwlat detector") Cc: stable@vger.kernel.org Signed-off-by: Srivatsa S. Bhat (VMware) Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

sched/core: Provide a pointer to the valid CPU mask

2019-06-03T09:49:37Z

In commit: 4b53a3412d66 ("sched/core: Remove the tsk_nr_cpus_allowed() wrapper") the tsk_nr_cpus_allowed() wrapper was removed. There was not much difference in !RT but in RT we used this to implement migrate_disable(). Within a migrate_disable() section the CPU mask is restricted to single CPU while the "normal" CPU mask remains untouched. As an alternative implementation Ingo suggested to use: struct task_struct { const cpumask_t *cpus_ptr; cpumask_t cpus_mask; }; with t->cpus_ptr = &t->cpus_mask; In -RT we then can switch the cpus_ptr to: t->cpus_ptr = &cpumask_of(task_cpu(p)); in a migration disabled region. The rules are simple: - Code that 'uses' ->cpus_allowed would use the pointer. - Code that 'modifies' ->cpus_allowed would use the direct mask. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Thomas Gleixner Cc: Linus Torvalds Cc: Peter Zijlstra Link: https://lkml.kernel.org/r/20190423142636.14347-1-bigeasy@linutronix.de Signed-off-by: Ingo Molnar

tracing: Add SPDX License format tags to tracing files

2018-08-16T23:08:06Z

Add the SPDX License header to ease license compliance management. Signed-off-by: Steven Rostedt (VMware)

tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists

2018-08-01T20:06:02Z

The start function of the hwlat tracer should never be called when the hwlat thread already exists. If it is called, do a WARN_ON(). Signed-off-by: Steven Rostedt (VMware)

ftrace: Add missing check for existing hwlat thread

2018-08-01T20:04:24Z

The hwlat tracer uses a kernel thread to measure latencies. The function that creates this kernel thread, start_kthread(), can be called when the tracer is initialized and when the tracer is explicitly enabled. start_kthread() does not check if there is an existing hwlat kernel thread and will create a new one each time it is called. This causes the reference to the previous thread to be lost. Without the thread reference, the old kernel thread becomes unstoppable and continues to use CPU time even after the hwlat tracer has been disabled. This problem can be observed when a system is booted with tracing enabled and the hwlat tracer is configured like this: echo hwlat > current_tracer; echo 1 > tracing_on Add the missing check for an existing kernel thread in start_kthread() to prevent this problem. This function and the rest of the hwlat kernel thread setup and teardown are already serialized because they are called through the tracer core code with trace_type_lock held. [ Note, this only fixes the symptom. The real fix was not to call this function when tracing_on was already one. But this still makes the code more robust, so we'll add it. ] Link: http://lkml.kernel.org/r/1533120354-22923-1-git-send-email-erica.bugden@linutronix.de Signed-off-by: Erica Bugden Signed-off-by: Steven Rostedt (VMware)

trace: make trace_hwlat timestamp y2038 safe

2017-05-09T00:15:15Z

struct timespec is not y2038 safe on 32 bit machines and needs to be replaced by struct timespec64 in order to represent times beyond year 2038 on such machines. Fix all the timestamp representation in struct trace_hwlat and all the corresponding implementations. Link: http://lkml.kernel.org/r/1491613030-11599-3-git-send-email-deepa.kernel@gmail.com Signed-off-by: Deepa Dinamani Acked-by: Steven Rostedt (VMware) Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:27Z

We are going to split out of , which will have to be picked up from other headers and .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

Merge tag 'trace-v4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2017-02-27T21:36:19Z

Pull another tracing update from Steven Rostedt: "Commit 79c6f448c8b79c ("tracing: Fix hwlat kthread migration") fixed a bug that was caused by a race condition in initializing the hwlat thread. When fixing this code, I realized that it should have been done differently. Instead of doing the rewrite and sending that to stable, I just sent the above commit to fix the bug that should be back ported. This commit is on top of the quick fix commit to rewrite the code the way it should have been written in the first place" * tag 'trace-v4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Clean up the hwlat binding code

Merge tag 'trace-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2017-02-27T21:26:17Z

Pull tracing updates from Steven Rostedt: "This release has no new tracing features, just clean ups, minor fixes and small optimizations" * tag 'trace-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (25 commits) tracing: Remove outdated ring buffer comment tracing/probes: Fix a warning message to show correct maximum length tracing: Fix return value check in trace_benchmark_reg() tracing: Use modern function declaration jump_label: Reduce the size of struct static_key tracing/probe: Show subsystem name in messages tracing/hwlat: Update old comment about migration timers: Make flags output in the timer_start tracepoint useful tracing: Have traceprobe_probes_write() not access userspace unnecessarily tracing: Have COMM event filter key be treated as a string ftrace: Have set_graph_function handle multiple functions in one write ftrace: Do not hold references of ftrace_graph_{notrace_}hash out of graph_lock tracing: Reset parser->buffer to allow multiple "puts" ftrace: Have set_graph_functions handle write with RDWR ftrace: Reset fgd->hash in ftrace_graph_write() ftrace: Replace (void *)1 with a meaningful macro name FTRACE_GRAPH_EMPTY ftrace: Create a slight optimization on searching the ftrace_hash tracing: Add ftrace_hash_key() helper function ftrace: Convert graph filter to use hash tables ftrace: Expose ftrace_hash_empty and ftrace_lookup_ip ...