- 13 Jan, 2022 16 commits
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Daniel Bristot de Oliveira authored
The rtla osnoise hist tool collects all osnoise:sample_threshold occurrence in a histogram, displaying the results in a user-friendly way. The tool also allows many configurations of the osnoise tracer and the collection of the tracer output. Here is one example of the rtla osnoise hist tool output: ---------- %< ---------- [root@f34 ~]# rtla osnoise hist --bucket-size 10 --entries 100 -c 0-8 -d 1M -r 9000 -P F:1 # RTLA osnoise histogram # Time unit is microseconds (us) # Duration: 0 00:01:00 Index CPU-000 CPU-001 CPU-002 CPU-003 CPU-004 CPU-005 CPU-006 CPU-007 CPU-008 0 430 434 352 455 440 463 467 436 484 10 88 88 92 141 120 100 126 166 100 20 19 7 12 22 8 8 13 13 16 30 6 0 2 0 1 2 2 1 0 50 0 0 0 0 0 0 1 0 0 over: 0 0 0 0 0 0 0 0 0 count: 543 529 458 618 569 573 609 616 600 min: 0 0 0 0 0 0 0 0 0 avg: 0 0 0 0 0 0 0 0 0 max: 30 20 30 20 30 30 50 30 20 ---------- >% ---------- Running - rtla osnoise hist --help provides information about the available options. Link: https://lkml.kernel.org/r/c68060544de89b8b62510ed91c7369f162eb465b.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by:
Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by:
Steven Rostedt <rostedt@goodmis.org>
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Daniel Bristot de Oliveira authored
The rtla osnoise tool is an interface for the osnoise tracer. The osnoise tracer dispatches a kernel thread per-cpu. These threads read the time in a loop while with preemption, softirqs and IRQs enabled, thus allowing all the sources of osnoise during its execution. The osnoise threads take note of the entry and exit point of any source of interferences, increasing a per-cpu interference counter. The osnoise tracer also saves an interference counter for each source of interference. The rtla osnoise top mode displays information about the periodic summary from the osnoise tracer. One example of rtla osnoise top output is: [root@alien ~]# rtla osnoise top -c 0-3 -d 1m -q -r 900000 -P F:1 Operating System Noise duration: 0 00:01:00 | time is in us CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI IRQ Softirq Thread 0 #58 52200000 1031 99.99802 91 60 0 0 52285 0 101 1 #59 53100000 5 99.99999 5 5 0 9 53122 0 18 2 #59 53100000 7 99.99998 7 7 0 8 53115 0 18 3 #59 53100000 8274 99.98441 277 23 0 9 53778 0 660 "rtla osnoise top --help" works and provide information about the available options. Link: https://lkml.kernel.org/r/0d796993abf587ae5a170bb8415c49368d4999e1.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: -
Daniel Bristot de Oliveira authored
The osnoise tool is the interface for the osnoise tracer. The osnoise tool will have multiple "modes" with different outputs. At this point, no mode is included. The osnoise.c includes the osnoise_context abstraction. It serves to read-save-change-restore the default values from tracing/osnoise/ directory. When the context is deleted, the default values are restored. It also includes some other helper functions for managing osnoise tracer sessions. With these bits and pieces in place, we can start adding some functionality to rtla. Link: https://lkml.kernel.org/r/2d44c21ff561f503b4c7b1813892761818118460.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by:
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Daniel Bristot de Oliveira authored
This is a set of utils and tracer helper functions. They are used by rtla mostly to parse config, display data and some trace operations that are not part of libtracefs (because they are only useful it for this case). Link: https://lkml.kernel.org/r/a94c128aba9e6e66d502b7094f2e8c7ac95b12e5.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by:
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Daniel Bristot de Oliveira authored
The rtla is a meta-tool that includes a set of commands that aims to analyze the real-time properties of Linux. But instead of testing Linux as a black box, rtla leverages kernel tracing capabilities to provide precise information about the properties and root causes of unexpected results. rtla --help works and provide information about the available options. This is just the "main" and the Makefile, no function yet. Link: https://lkml.kernel.org/r/bf9118ed43a09e6c054c9a491cbe7411ad1acd89.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by:
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Nikita Yushchenko authored
If start_per_cpu_kthreads() called from osnoise_workload_start() returns error, event hooks are left in broken state: unhook_irq_events() called but unhook_thread_events() and unhook_softirq_events() not called, and trace_osnoise_callback_enabled flag not cleared. On the next tracer enable, hooks get not installed due to trace_osnoise_callback_enabled flag. And on the further tracer disable an attempt to remove non-installed hooks happened, hitting a WARN_ON_ONCE() in tracepoint_remove_func(). Fix the error path by adding the missing part of cleanup. While at this, introduce osnoise_unhook_events() to avoid code duplication between this error path and normal tracer disable. Link: https://lkml.kernel.org/r/20220109153459.3701773-1-nikita.yushchenko@virtuozzo.com Cc: stable@vger.kernel.org Fixes: bce29ac9 ("trace: Add osnoise tracer") Acked-by:
Nikita Yushchenko <nikita.yushchenko@virtuozzo.com> Signed-off-by:
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Yuntao Wang authored
Since the same warning message is already printed in the trace_create_file() function, there is no need to print it again. Link: https://lkml.kernel.org/r/20220109162232.361747-1-ytcoode@gmail.comSigned-off-by:
Yuntao Wang <ytcoode@gmail.com> Signed-off-by:
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Xiangyang Zhang authored
The 'nmissed' column of the 'kprobe_profile' file for kretprobe is not showed correctly, kretprobe can be skipped by two reasons, shortage of kretprobe_instance which is counted by tk->rp.nmissed, and kprobe itself is missed by some reason, so to show the sum. Link: https://lkml.kernel.org/r/20220107150242.5019-1-xyz.sun.ok@gmail.com Cc: stable@vger.kernel.org Fixes: 4a846b44 ("tracing/kprobes: Cleanup kprobe tracer code") Acked-by:
Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by:
Xiangyang Zhang <xyz.sun.ok@gmail.com> Signed-off-by:
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Steven Rostedt authored
Pingfan reported that the following causes a fault: echo "filename ~ \"cpu\"" > events/syscalls/sys_enter_openat/filter echo 1 > events/syscalls/sys_enter_at/enable The reason is that trace event filter treats the user space pointer defined by "filename" as a normal pointer to compare against the "cpu" string. The following bug happened: kvm-03-guest16 login: [72198.026181] BUG: unable to handle page fault for address: 00007fffaae8ef60 #PF: supervisor read access in kernel mode #PF: error_code(0x0001) - permissions violation PGD 80000001008b7067 P4D 80000001008b7067 PUD 2393f1067 PMD 2393ec067 PTE 8000000108f47867 Oops: 0001 [#1] PREEMPT SMP PTI CPU: 1 PID: 1 Comm: systemd Kdump: loaded Not tainted 5.14.0-32.el9.x86_64 #1 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:strlen+0x0/0x20 Code: 48 89 f9 74 09 48 83 c1 01 80 39 00 75 f7 31 d2 44 0f b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 0f 1f 80 00 00 00 00 <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 31 RSP: 0018:ffffb5b900013e48 EFLAGS: 00010246 RAX: 0000000000000018 RBX: ffff8fc1c49ede00 RCX: 0000000000000000 RDX: 0000000000000020 RSI: ffff8fc1c02d601c RDI: 00007fffaae8ef60 RBP: 00007fffaae8ef60 R08: 0005034f4ddb8ea4 R09: 0000000000000000 R10: ffff8fc1c02d601c R11: 0000000000000000 R12: ffff8fc1c8a6e380 R13: 0000000000000000 R14: ffff8fc1c02d6010 R15: ffff8fc1c00453c0 FS: 00007fa86123db40(0000) GS:ffff8fc2ffd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffaae8ef60 CR3: 0000000102880001 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: filter_pred_pchar+0x18/0x40 filter_match_preds+0x31/0x70 ftrace_syscall_enter+0x27a/0x2c0 syscall_trace_enter.constprop.0+0x1aa/0x1d0 do_syscall_64+0x16/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fa861d88664 The above happened because the kernel tried to access user space directly and triggered a "supervisor read access in kernel mode" fault. Worse yet, the memory could not even be loaded yet, and a SEGFAULT could happen as well. This could be true for kernel space accessing as well. To be even more robust, test both kernel and user space strings. If the string fails to read, then simply have the filter fail. Note, TASK_SIZE is used to determine if the pointer is user or kernel space and the appropriate strncpy_from_kernel/user_nofault() function is used to copy the memory. For some architectures, the compare to TASK_SIZE may always pick user space or kernel space. If it gets it wrong, the only thing is that the filter will fail to match. In the future, this needs to be fixed to have the event denote which should be used. But failing a filter is much better than panicing the machine, and that can be solved later. Link: https://lore.kernel.org/all/20220107044951.22080-1-kernelfans@gmail.com/ Link: https://lkml.kernel.org/r/20220110115532.536088fd@gandalf.local.home Cc: stable@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Reported-by:Pingfan Liu <kernelfans@gmail.com> Tested-by:
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Steven Rostedt authored
Currently, the syscall trace events call trace_buffer_lock_reserve() directly, which means that it misses out on some of the filtering optimizations provided by the helper function trace_event_buffer_lock_reserve(). Have the syscall trace events call that instead, as it was missed when adding the update to use the temp buffer when filtering. Link: https://lkml.kernel.org/r/20220107225839.823118570@goodmis.org Cc: stable@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tom Zanussi <zanussi@kernel.org> Reviewed-by:
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Geliang Tang authored
Here __assign_str_len() should be used for the __string_len type, instead of __assign_str() in the comment. Link: https://lkml.kernel.org/r/5c012db463392d0e6d4f0636203d778962ad060a.1640170494.git.geliang.tang@suse.comReviewed-by:
Geliang Tang <geliang.tang@suse.com> Signed-off-by:
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Steven Rostedt (VMware) authored
Now that ftrace function pointers are sorted at compile time, add a test that makes sure they are sorted at run time. This test is only run if it is configured in. Link: https://lkml.kernel.org/r/20211206151858.4d21a24d@gandalf.local.home Cc: Yinan Liu <yinan@linux.alibaba.com> Signed-off-by:
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Yinan Liu authored
When the kernel starts, the initialization of ftrace takes up a portion of the time (approximately 6~8ms) to sort mcount addresses. We can save this time by moving mcount-sorting to compile time. Link: https://lkml.kernel.org/r/20211212113358.34208-2-yinan@linux.alibaba.comSigned-off-by:
Yinan Liu <yinan@linux.alibaba.com> Reported-by:
kernel test robot <lkp@intel.com> Reported-by:
kernel test robot <oliver.sang@intel.com> Signed-off-by:
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Xiaoke Wang authored
kstrndup() is a memory allocation-related function, it returns NULL when some internal memory errors happen. It is better to check the return value of it so to catch the memory error in time. Link: https://lkml.kernel.org/r/tencent_4D6E270731456EB88712ED7F13883C334906@qq.comAcked-by:
Xiaoke Wang <xkernel.wang@foxmail.com> Signed-off-by:
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Xiaoke Wang authored
kstrdup() returns NULL when some internal memory errors happen, it is better to check the return value of it so to catch the memory error in time. Link: https://lkml.kernel.org/r/tencent_3C2E330722056D7891D2C83F29C802734B06@qq.comAcked-by:
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Sebastian Andrzej Siewior authored
Disabling only bottom halves via local_bh_disable() disables also preemption but this remains invisible to tracing. On a CONFIG_PREEMPT kernel one might wonder why there is no scheduling happening despite the N flag in the trace. The reason might be the a rcu_read_lock_bh() section. Add a 'b' to the tracing output if in task context with disabled bottom halves. Link: https://lkml.kernel.org/r/YbcbtdtC/bjCKo57@linutronix.deSigned-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
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- 10 Jan, 2022 4 commits
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Tom Zanussi authored
The event_command.parse() callback is responsible for parsing and registering triggers. The existing command implementions for this callback duplicate a lot of the same code, so to clean up and consolidate those implementations, introduce a handful of helper functions for implementors to use. This also makes it easier for new commands to be implemented and allows them to focus more on the customizations they provide rather than obscuring and complicating it with boilerplate code. Link: https://lkml.kernel.org/r/c1ff71f594d45177706571132bd3119491097221.1641823001.git.zanussi@kernel.orgSigned-off-by:
Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Tom Zanussi authored
The event_trigger_ops for an event_command are already accessible via event_trigger_data.ops so remove the redundant ops from the callback. Link: https://lkml.kernel.org/r/4c6f2a41820452f9cacddc7634ad442928aa2aa6.1641823001.git.zanussi@kernel.orgSigned-off-by:
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Tom Zanussi authored
The name of the func() callback on event_trigger_ops is too generic and is easily confused with other callbacks with that name, so change it to something that reflects its actual purpose. In this case, the main purpose of the callback is to implement an event trigger, so call it trigger() instead. Also add some more documentation to event_trigger_ops describing the callbacks a bit better. Link: https://lkml.kernel.org/r/36ab812e3ee74ee03ae0043fda41a858ee728c00.1641823001.git.zanussi@kernel.orgSigned-off-by:
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Tom Zanussi authored
The name of the func() callback on event_command is too generic and is easily confused with other callbacks with that name, so change it to something that reflects its actual purpose. In this case, the main purpose of the callback is to parse an event command, so call it parse() instead. Link: https://lkml.kernel.org/r/7784e321840752ed88aac0b349c0c685fc9247b1.1641823001.git.zanussi@kernel.orgSigned-off-by:
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- 11 Dec, 2021 6 commits
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Steven Rostedt (VMware) authored
Currently tracing_read_pipe() open codes trace_iterator_reset(). Just have it use trace_iterator_reset() instead. Link: https://lkml.kernel.org/r/20211210202616.64d432d2@gandalf.local.homeSigned-off-by:
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Xiu Jianfeng authored
Make use of memset_startat helper to simplify the code, there should be no functional change as a result of this patch. Link: https://lkml.kernel.org/r/20211210012245.207489-1-xiujianfeng@huawei.comSigned-off-by:
Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by:
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Beau Belgrave authored
synth_events is returning -EINVAL if the dyn_event create command does not contain ' \t'. This prevents other systems from getting called back. synth_events needs to return -ECANCELED in these cases when the command is not targeting the synth_event system. Link: https://lore.kernel.org/linux-trace-devel/20210930223821.11025-1-beaub@linux.microsoft.com Fixes: c9e759b1 ("tracing: Rework synthetic event command parsing") Reviewed-by:
Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by:
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Jiri Olsa authored
As suggested by Linus [1] using list_for_each_entry to iterate directly trace_[ku]probe objects so we can skip another call to container_of in these loops. [1] https://lore.kernel.org/r/CAHk-=wjakjw6-rDzDDBsuMoDCqd+9ogifR_EE1F0K-jYek1CdA@mail.gmail.com Link: https://lkml.kernel.org/r/20211125202852.406405-1-jolsa@kernel.orgSuggested-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Jiri Olsa <jolsa@kernel.org> Acked-by:
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Steven Rostedt (VMware) authored
Instead of referencing the inode from a dentry via dentry->d_inode, use the helper function d_inode(dentry) instead. This is the considered the correct way to access it. Reported-by:
Christian Brauner <christian.brauner@ubuntu.com> Reported: https://lore.kernel.org/all/20211208104454.nhxyvmmn6d2qhpwl@wittgenstein/Signed-off-by:
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Yinan Liu authored
Modified the code style issue of if() {}, keep the code style consistent. Link: https://lkml.kernel.org/r/20211207151348.54921-3-yinan@linux.alibaba.comSigned-off-by:
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- 08 Dec, 2021 1 commit
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John Keeping authored
The tracing marker files are write-only streams with no meaningful concept of file position. Using stream_open() to mark them as stream-link indicates this and has the added advantage that a single file descriptor can now be used from multiple threads without contention thanks to clearing FMODE_ATOMIC_POS. Note that this has the potential to break existing userspace by since both lseek(2) and pwrite(2) will now return ESPIPE when previously lseek would have updated the stored offset and pwrite would have appended to the trace. A survey of libtracefs and several other projects found to use trace_marker(_raw) [1][2][3] suggests that everyone limits themselves to calling write(2) and close(2) on these file descriptors so there is a good chance this will go unnoticed and the benefits of reduced overhead and lock contention seem worth the risk. [1] https://github.com/google/perfetto [2] https://github.com/intel/media-driver/ [3] https://w1.fi/cgit/hostap/ Link: https://lkml.kernel.org/r/20211207142558.347029-1-john@metanate.comSigned-off-by:
John Keeping <john@metanate.com> Signed-off-by:
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- 06 Dec, 2021 13 commits
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Uladzislau Rezki (Sony) authored
Instead of invoking a synchronize_rcu() to free a pointer after a grace period we can directly make use of new API that does the same but in more efficient way. Link: https://lkml.kernel.org/r/20211124110308.2053-10-urezki@gmail.comSigned-off-by:
Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by:
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Qiujun Huang authored
It's named field here. Link: https://lkml.kernel.org/r/20210516022410.64271-1-hqjagain@gmail.comSigned-off-by:
Qiujun Huang <hqjagain@gmail.com> Signed-off-by:
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Steven Rostedt (VMware) authored
To be consistent with kprobes and eprobes, use trace_event_buffer_reserver() and trace_event_buffer_commit(). This will ensure that any updates to trace events will also be implemented on uprobe events. Link: https://lkml.kernel.org/r/20211206162440.69fbf96c@gandalf.local.homeAcked-by:
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Steven Rostedt (VMware) authored
As kprobe events use trace_event_buffer_commit() to commit the event to the ftrace ring buffer, for consistency, it should use trace_event_buffer_reserve() to allocate it, as the two functions are related. Link: https://lkml.kernel.org/r/20211130024319.257430762@goodmis.orgAcked-by:
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Steven Rostedt (VMware) authored
The eprobes open code the reserving of the event on the ring buffer for ftrace instead of using the ftrace event wrappers, which means that it doesn't get affected by the filters, breaking the filtering logic on user space. Link: https://lkml.kernel.org/r/20211130024319.068451680@goodmis.orgSigned-off-by:
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Steven Rostedt (VMware) authored
In case trace_event_buffer_lock_reserve() is called with preemption enabled, the algorithm that defines the usage of the per cpu filter buffer may fail if the task schedules to another CPU after determining which buffer it will use. Disable preemption when using the filter buffer. And because that same buffer must be used throughout the call, keep preemption disabled until the filter buffer is released. This will also keep the semantics between the use case of when the filter buffer is used, and when the ring buffer itself is used, as that case also disables preemption until the ring buffer is released. Link: https://lkml.kernel.org/r/20211130024318.880190623@goodmis.org [ Fixed warning of assignment in if statement Reported-by: kernel test robot <lkp@intel.com> ] Signed-off-by:
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Steven Rostedt (VMware) authored
The value read by this_cpu_read() is used later and its use is expected to stay on the same CPU as being read. But this_cpu_read() does not warn if it is called without preemption disabled, where as __this_cpu_read() will check if preemption is disabled on CONFIG_DEBUG_PREEMPT Currently all callers have preemption disabled, but there may be new callers in the future that may not. Link: https://lkml.kernel.org/r/20211130024318.698165354@goodmis.orgSigned-off-by:
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Masami Hiramatsu authored
Add new '__rel_loc' dynamic data location attribute support. This type attribute is similar to the '__data_loc' but records the offset from the field itself. The libtraceevent adds TEP_FIELD_IS_RELATIVE to the 'tep_format_field::flags' with TEP_FIELD_IS_DYNAMIC for'__rel_loc'. Link: https://lkml.kernel.org/r/163757344810.510314.12449413842136229871.stgit@devnote2 Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Masami Hiramatsu authored
Add '__rel_loc' new dynamic data location attribute which encodes the data location from the next to the field itself. This is similar to the '__data_loc' but the location offset is not from the event entry but from the next of the field. This patch adds '__rel_loc' decoding support in the libtraceevent. Link: https://lkml.kernel.org/r/163757343994.510314.13241077597729303802.stgit@devnote2 Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Masami Hiramatsu authored
Add '__rel_loc' using sample event for testing. User can use this for testing purpose. There is no reason to use this macro from the kernel. Link: https://lkml.kernel.org/r/163757343050.510314.2876529802471645178.stgit@devnote2 Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Masami Hiramatsu authored
Add '__rel_loc' using trace event macros. These macros are usually not used in the kernel, except for testing purpose. This also add "rel_" variant of macros for dynamic_array string, and bitmask. Link: https://lkml.kernel.org/r/163757342119.510314.816029622439099016.stgit@devnote2 Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Masami Hiramatsu authored
Add '__rel_loc' new dynamic data location attribute which encodes the data location from the next to the field itself. The '__data_loc' is used for encoding the dynamic data location on the trace event record. But '__data_loc' is not useful if the writer doesn't know the event header (e.g. user event), because it records the dynamic data offset from the entry of the record, not the field itself. This new '__rel_loc' attribute encodes the data location relatively from the next of the field. For example, when there is a record like below (the number in the parentheses is the size of fields) |header(N)|common(M)|fields(K)|__data_loc(4)|fields(L)|data(G)| In this case, '__data_loc' field will be __data_loc = (G << 16) | (N+M+K+4+L) If '__rel_loc' is used, this will be |header(N)|common(M)|fields(K)|__rel_loc(4)|fields(L)|data(G)| where __rel_loc = (G << 16) | (L) This case shows L bytes after the '__rel_loc' attribute field, if there is no fields after the __rel_loc field, L must be 0. This is relatively easy (and no need to consider the kernel header change) when the event data fields are composed by user who doesn't know header and common fields. Link: https://lkml.kernel.org/r/163757341258.510314.4214431827833229956.stgit@devnote2 Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Colin Ian King authored
There is a spelling mistake in the tracing mini-HOWTO text. Fix it. Link: https://lkml.kernel.org/r/20211108201513.42876-1-colin.i.king@gmail.comSigned-off-by:
Colin Ian King <colin.i.king@gmail.com> Signed-off-by:
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