- 20 Aug, 2021 1 commit
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Tzvetomir Stoyanov (VMware) authored
A new dynamic event is introduced: event probe. The event is attached to an existing tracepoint and uses its fields as arguments. The user can specify custom format string of the new event, select what tracepoint arguments will be printed and how to print them. An event probe is created by writing configuration string in 'dynamic_events' ftrace file: e[:[SNAME/]ENAME] SYSTEM/EVENT [FETCHARGS] - Set an event probe -:SNAME/ENAME - Delete an event probe Where: SNAME - System name, if omitted 'eprobes' is used. ENAME - Name of the new event in SNAME, if omitted the SYSTEM_EVENT is used. SYSTEM - Name of the system, where the tracepoint is defined, mandatory. EVENT - Name of the tracepoint event in SYSTEM, mandatory. FETCHARGS - Arguments: <name>=$<field>[:TYPE] - Fetch given filed of the tracepoint and print it as given TYPE with given name. Supported types are: (u8/u16/u32/u64/s8/s16/s32/s64), basic type (x8/x16/x32/x64), hexadecimal types "string", "ustring" and bitfield. Example, attach an event probe on openat system call and print name of the file that will be opened: echo "e:esys/eopen syscalls/sys_enter_openat file=\$filename:string" >> dynamic_events A new dynamic event is created in events/esys/eopen/ directory. It can be deleted with: echo "-:esys/eopen" >> dynamic_events Filters, triggers and histograms can be attached to the new event, it can be matched in synthetic events. There is one limitation - an event probe can not be attached to kprobe, uprobe or another event probe. Link: https://lkml.kernel.org/r/20210812145805.2292326-1-tz.stoyanov@gmail.com Link: https://lkml.kernel.org/r/20210819152825.142428383@goodmis.orgAcked-by:Masami Hiramatsu <mhiramat@kernel.org> Co-developed-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:
Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> Signed-off-by:
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- 19 Aug, 2021 3 commits
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Masami Hiramatsu authored
Since kprobe_events and uprobe_events only check whether the other same-type probe event has the same name or not, if the user gives the same name of the existing tracepoint event (or the other type of probe events), it silently fails to create the tracefs entry (but registered.) as below. /sys/kernel/tracing # ls events/task/task_rename enable filter format hist id trigger /sys/kernel/tracing # echo p:task/task_rename vfs_read >> kprobe_events [ 113.048508] Could not create tracefs 'task_rename' directory /sys/kernel/tracing # cat kprobe_events p:task/task_rename vfs_read To fix this issue, check whether the existing events have the same name or not in trace_probe_register_event_call(). If exists, it rejects to register the new event. Link: https://lkml.kernel.org/r/162936876189.187130.17558311387542061930.stgit@devnote2Signed-off-by:
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Steven Rostedt (VMware) authored
In preparation to allow event probes to use the process_fetch_insn() callback in trace_probe_tmpl.h, change the data passed to it from a pointer to pt_regs, as the event probe will not be using regs, and make it a void pointer instead. Update the process_fetch_insn() callers for kprobe and uprobe events to have the regs defined in the function and just typecast the void pointer parameter. Link: https://lkml.kernel.org/r/20210819041842.291622924@goodmis.orgAcked-by:
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Steven Rostedt (VMware) authored
Instead of a boolean "is_return" have traceprobe_set_print_fmt() take a type (currently just PROBE_PRINT_NORMAL and PROBE_PRINT_RETURN). This will simplify adding different types. For example, the development of the event_probe, will need its own type as it prints an event, and not an IP. Link: https://lkml.kernel.org/r/20210819041842.104626301@goodmis.orgAcked-by:
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- 18 Aug, 2021 5 commits
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Steven Rostedt (VMware) authored
Remove SIZEOF_TRACE_KPROBE() and SIZEOF_TRACE_UPROBE() and use struct_size() as that's what it is made for. No need to have custom macros. Especially since struct_size() has some extra memory checks for correctness. Link: https://lkml.kernel.org/r/20210817035027.795000217@goodmis.orgAcked-by:
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Steven Rostedt (VMware) authored
Kprobe and uprobe events can add a "system" to the events that are created via the kprobe_events and uprobe_events files respectively. If they do not include a "system" in the name, then the default "kprobes" or "uprobes" is used. The current notation to specify a system for one of these probe events is to add a '/' delimiter in the name, where the content before the '/' will be the system to use, and the content after will be the event name. echo 'p:my_system/my_event' > kprobe_events But this is inconsistent with the way histogram triggers separate their system / event names. The histogram triggers use a '.' delimiter, which can be confusing. To allow this to be more consistent, as well as keep backward compatibility, allow the kprobe and uprobe events to denote a system name with either a '/' or a '.'. That is: echo 'p:my_system/my_event' > kprobe_events is equivalent to: echo 'p:my_system.my_event' > kprobe_events Link: https://lore.kernel.org/linux-trace-devel/20210813004448.51c7de69ce432d338f4d226b@kernel.org/ Link: https://lkml.kernel.org/r/20210817035027.580493202@goodmis.orgSuggested-by:
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Steven Rostedt (VMware) authored
The two places that call traceprobe_parse_probe_arg() allocate a temporary buffer to copy the argv[i] into, because argv[i] is constant and the traceprobe_parse_probe_arg() will modify it to do the parsing. These two places allocate this buffer and then free it right after calling this function, leaving the onus of this allocation to the caller. As there's about to be a third user of this function that will have to do the same thing, instead of having the caller allocate the temporary buffer, simply move that allocation into the traceprobe_parse_probe_arg() itself, which will simplify the code of the callers. Link: https://lkml.kernel.org/r/20210817035027.385422828@goodmis.orgAcked-by:
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Steven Rostedt (VMware) authored
As dynamic events are not created by modules, if something is attached to one, calling "try_module_get()" on its "mod" field, is not going to keep the dynamic event from going away. Since dynamic events do not need the "mod" pointer of the event structure, make a union out of it in order to save memory (there's one structure for each of the thousand+ events in the kernel), and have any event with the DYNAMIC flag set to use a ref counter instead. Link: https://lore.kernel.org/linux-trace-devel/20210813004448.51c7de69ce432d338f4d226b@kernel.org/ Link: https://lkml.kernel.org/r/20210817035027.174869074@goodmis.orgSuggested-by:
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Steven Rostedt (VMware) authored
To differentiate between static and dynamic events, add a new flag DYNAMIC to the event flags that all dynamic events have set. This will allow to differentiate when attaching to a dynamic event from a static event. Static events have a mod pointer that references the module they were created in (or NULL for core kernel). This can be incremented when the event has something attached to it. But there exists no such mechanism for dynamic events. This is dangerous as the dynamic events may now disappear without the "attachment" knowing that it no longer exists. To enforce the dynamic flag, change dyn_event_add() to pass the event that is being created such that it can set the DYNAMIC flag of the event. This helps make sure that no location that creates a dynamic event misses setting this flag. Link: https://lore.kernel.org/linux-trace-devel/20210813004448.51c7de69ce432d338f4d226b@kernel.org/ Link: https://lkml.kernel.org/r/20210817035026.936958254@goodmis.orgSuggested-by:
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- 17 Aug, 2021 1 commit
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Sebastian Andrzej Siewior authored
The functions get_online_cpus() and put_online_cpus() have been deprecated during the CPU hotplug rework. They map directly to cpus_read_lock() and cpus_read_unlock(). Replace deprecated CPU-hotplug functions with the official version. The behavior remains unchanged. Link: https://lkml.kernel.org/r/20210803141621.780504-37-bigeasy@linutronix.de Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Acked-by:
Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
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- 16 Aug, 2021 20 commits
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Steven Rostedt (VMware) authored
The "latency" tracers have some different requirements than normal tracing, and also includes Daniel as a maintainer. Add a section in the MAINTAINERS file to help direct patches and bug reports to these tracers to the right people. Signed-off-by: -
zhaoxiao authored
Fix function name in tracepoint.c kernel-doc comment to remove a warning found by clang_w1. kernel/tracepoint.c:589: warning: expecting prototype for register_tracepoint_notifier(). Prototype was for register_tracepoint_module_notifier() instead kernel/tracepoint.c:613: warning: expecting prototype for unregister_tracepoint_notifier(). Prototype was for unregister_tracepoint_module_notifier() instead Link: https://lkml.kernel.org/r/20210816052430.16539-1-zhaoxiao@uniontech.comAcked-by:
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by:
zhaoxiao <zhaoxiao@uniontech.com> Signed-off-by:
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Masami Hiramatsu authored
Update ktest example for the boot-time tracing with histogram options. Note that since the histogram option uses "trace()" action instead of "EVENT()", this updates the matching pattern too. Link: https://lkml.kernel.org/r/162856130208.203126.4458319094852152589.stgit@devnote2Signed-off-by:
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Masami Hiramatsu authored
Use per-group/all enable option instead of ftrace.events option. This will make the bootconfig file more readable. Link: https://lkml.kernel.org/r/162856129436.203126.12462564671412940618.stgit@devnote2Signed-off-by:
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Masami Hiramatsu authored
Add histogram syntax support to bconf2ftrace.sh script. Link: https://lkml.kernel.org/r/162856128672.203126.8240335908303312607.stgit@devnote2Signed-off-by:
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Masami Hiramatsu authored
Add group or all event enabling syntax support to bconf2ftrace.sh. User can pass a bootconfig file which includes ftrace[.instance.INSTANCE].event.enable and ftrace[.instance.INSTANCE].event.GROUP.enable correctly. Link: https://lkml.kernel.org/r/162856127850.203126.16694505101982548237.stgit@devnote2Signed-off-by: -
Masami Hiramatsu authored
Add the documentation about histogram syntax in boot-time tracing. This will allow user to write the histogram setting in a structured parameters. Link: https://lkml.kernel.org/r/162856127129.203126.15551542847575916525.stgit@devnote2Signed-off-by:
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Masami Hiramatsu authored
Since trigger_process_regex() modifies given trigger actions while parsing, the error message couldn't show what command was passed to the trigger_process_regex() when it returns an error. To fix that, show the backed up trigger action command instead of parsed buffer. Link: https://lkml.kernel.org/r/162856126413.203126.9465564928450701424.stgit@devnote2Signed-off-by:
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Masami Hiramatsu authored
Add multiple histograms support for each event. This allows user to set multiple histograms to an event. ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] { ... } The 'N' is a digit started string and it can be omitted for the default histogram. For example, multiple hist triggers example in the Documentation/trace/histogram.rst can be written as below; ftrace.event.net.netif_receive_skb.hist { 1 { keys = skbaddr.hex values = len filter = len < 0 } 2 { keys = skbaddr.hex values = len filter = len > 4096 } 3 { keys = skbaddr.hex values = len filter = len == 256 } 4 { keys = skbaddr.hex values = len } 5 { keys = len values = common_preempt_count } } Link: https://lkml.kernel.org/r/162856125628.203126.15846930277378572120.stgit@devnote2Signed-off-by: -
Masami Hiramatsu authored
Support multiple handlers for per-event histogram in boot-time tracing. Since the histogram can register multiple same handler-actions with different parameters, this expands the syntax to support such cases. With this update, the 'onmax', 'onchange' and 'onmatch' handler subkeys under per-event histogram option will take a number subkeys optionally as below. (see [.N]) ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist { onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] } onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] } } The 'N' must be a digit (or digit started word). Thus user can add several handler-actions to the histogram, for example, ftrace.event.SOMEGROUP.SOMEEVENT.hist { keys = SOME_ID; lat = common_timestamp.usecs-$ts0 onmatch.1 { event = GROUP1.STARTEVENT1 trace = latency_event, SOME_ID, $lat } onmatch.2 { event = GROUP2.STARTEVENT2 trace = latency_event, SOME_ID, $lat } } Then, it can trace the elapsed time from GROUP1.STARTEVENT1 to SOMEGROUP.SOMEEVENT, and from GROUP2.STARTEVENT2 to SOMEGROUP.SOMEEVENT with SOME_ID key. Link: https://lkml.kernel.org/r/162856124905.203126.14913731908137885922.stgit@devnote2Signed-off-by: -
Masami Hiramatsu authored
Add a hist-trigger action syntax support to boot-time tracing. Currently, boot-time tracing supports per-event actions as option strings. However, for the histogram action, it has a special syntax and usually needs a long action definition. To make it readable and fit to the bootconfig syntax, this introduces a new options for histogram. Here are the histogram action options for boot-time tracing. ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist { keys = <KEY>[,...] values = <VAL>[,...] sort = <SORT-KEY>[,...] size = <ENTRIES> name = <HISTNAME> var { <VAR> = <EXPR> ... } pause|continue|clear onmax|onchange { var = <VAR>; <ACTION> [= <PARAM>] } onmatch { event = <EVENT>; <ACTION> [= <PARAM>] } filter = <FILTER> } Where <ACTION> is one of below; trace = <EVENT>, <ARG1>[, ...] save = <ARG1>[, ...] snapshot Link: https://lkml.kernel.org/r/162856124106.203126.10501871028479029087.stgit@devnote2Signed-off-by: -
Huang Shijie authored
It should be @prev_pid, not @prev_prid. Link: https://lkml.kernel.org/r/20210802140234.5383-1-shijie@os.amperecomputing.comSigned-off-by:
Huang Shijie <shijie@os.amperecomputing.com> Signed-off-by:
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Masahiro Yamada authored
Make architectures select TRACE_IRQFLAGS_SUPPORT instead of having many defines. Link: https://lkml.kernel.org/r/20210731052233.4703-2-masahiroy@kernel.orgAcked-by:
Heiko Carstens <hca@linux.ibm.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> #arch/arc Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by:
Catalin Marinas <catalin.marinas@arm.com> Acked-by:
Max Filippov <jcmvbkbc@gmail.com> Signed-off-by:
Masahiro Yamada <masahiroy@kernel.org> Signed-off-by:
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Masahiro Yamada authored
The entire FTRACE block is surrounded by 'if TRACING_SUPPORT' ... 'endif'. Using 'depends on' is a simpler way to guard FTRACE. Link: https://lkml.kernel.org/r/20210731052233.4703-1-masahiroy@kernel.orgSigned-off-by:
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Steven Rostedt (VMware) authored
Allow common_pid.execname to be saved in a variable in one histogram to be passed to another histogram that can pass it as a parameter to a synthetic event. ># echo 'hist:keys=pid:__arg__1=common_timestamp.usecs:arg2=common_pid.execname' \ > events/sched/sched_waking/trigger ># echo 'wakeup_lat s32 pid; u64 delta; char wake_comm[]' > synthetic_events ># echo 'hist:keys=next_pid:pid=next_pid,delta=common_timestamp.usecs-$__arg__1,exec=$arg2'\ ':onmatch(sched.sched_waking).trace(wakeup_lat,$pid,$delta,$exec)' \ > events/sched/sched_switch/trigger The above is a wake up latency synthetic event setup that passes the execname of the common_pid that woke the task to the scheduling of that task, which triggers a synthetic event that passes the original execname as a parameter to display it. ># echo 1 > events/synthetic/enable ># cat trace <idle>-0 [006] d..4 186.863801: wakeup_lat: pid=1306 delta=65 wake_comm=kworker/u16:3 <idle>-0 [000] d..4 186.863858: wakeup_lat: pid=163 delta=27 wake_comm=<idle> <idle>-0 [001] d..4 186.863903: wakeup_lat: pid=1307 delta=36 wake_comm=kworker/u16:4 <idle>-0 [000] d..4 186.863927: wakeup_lat: pid=163 delta=5 wake_comm=<idle> <idle>-0 [006] d..4 186.863957: wakeup_lat: pid=1306 delta=24 wake_comm=kworker/u16:3 sshd-1306 [006] d..4 186.864051: wakeup_lat: pid=61 delta=62 wake_comm=<idle> <idle>-0 [000] d..4 186.965030: wakeup_lat: pid=609 delta=18 wake_comm=<idle> <idle>-0 [006] d..4 186.987582: wakeup_lat: pid=1306 delta=65 wake_comm=kworker/u16:3 <idle>-0 [000] d..4 186.987639: wakeup_lat: pid=163 delta=27 wake_comm=<idle> Link: https://lkml.kernel.org/r/20210722142837.458596338@goodmis.orgReviewed-by:Tom Zanussi <zanussi@kernel.org> Reviewed-by:
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Steven Rostedt (VMware) authored
Instead of kstrdup("const", GFP_KERNEL), have the hist_field type simply assign the constant hist_field->type = "const"; And when the value passed to it is a variable, use "kstrdup_const(var, GFP_KERNEL);" which will just copy the value if the variable is already a constant. This saves on having to allocate when not needed. All frees of the hist_field->type will need to use kfree_const(). Link: https://lkml.kernel.org/r/20210722142837.280718447@goodmis.orgSuggested-by: -
Steven Rostedt (VMware) authored
Update both the tracefs README file as well as the histogram.rst to include an explanation of what the buckets modifier is and how to use it. Include an example with the wakeup_latency example for both log2 and the buckets modifiers as there was no existing log2 example. Link: https://lkml.kernel.org/r/20210707213922.167218794@goodmis.orgAcked-by:
Namhyung Kim <namhyung@kernel.org> Reviewed-by:
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Steven Rostedt (VMware) authored
There's been several times I wished the histogram logic had a "grouping" feature for the buckets. Currently, each bucket has a size of one. That is, if you trace the amount of requested allocations, each allocation is its own bucket, even if you are interested in what allocates 100 bytes or less, 100 to 200, 200 to 300, etc. Also, without grouping, it fills up the allocated histogram buckets quickly. If you are tracking latency, and don't care if something is 200 microseconds off, or 201 microseconds off, but want to track them by say 10 microseconds each. This can not currently be done. There is a log2 but that grouping get's too big too fast for a lot of cases. Introduce a "buckets=SIZE" command to each field where it will record in a rounded number. For example: ># echo 'hist:keys=bytes_req.buckets=100:sort=bytes_req' > events/kmem/kmalloc/trigger ># cat events/kmem/kmalloc/hist # event histogram # # trigger info: hist:keys=bytes_req.buckets=100:vals=hitcount:sort=bytes_req.buckets=100:size=2048 [active] # { bytes_req: ~ 0-99 } hitcount: 3149 { bytes_req: ~ 100-199 } hitcount: 1468 { bytes_req: ~ 200-299 } hitcount: 39 { bytes_req: ~ 300-399 } hitcount: 306 { bytes_req: ~ 400-499 } hitcount: 364 { bytes_req: ~ 500-599 } hitcount: 32 { bytes_req: ~ 600-699 } hitcount: 69 { bytes_req: ~ 700-799 } hitcount: 37 { bytes_req: ~ 1200-1299 } hitcount: 16 { bytes_req: ~ 1400-1499 } hitcount: 30 { bytes_req: ~ 2000-2099 } hitcount: 6 { bytes_req: ~ 4000-4099 } hitcount: 2168 { bytes_req: ~ 5000-5099 } hitcount: 6 Totals: Hits: 7690 Entries: 13 Dropped: 0 Link: https://lkml.kernel.org/r/20210707213921.980359719@goodmis.orgAcked-by: -
Masami Hiramatsu authored
Fixes a build error when CONFIG_HIST_TRIGGERS=n with boot-time tracing. Since the trigger_process_regex() is defined only when CONFIG_HIST_TRIGGERS=y, if it is disabled, the 'actions' event option also must be disabled. Link: https://lkml.kernel.org/r/162856123376.203126.582144262622247352.stgit@devnote2 Fixes: 81a59555 ("tracing/boot: Add per-event settings") Signed-off-by:
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Pingfan Liu authored
The event filters are not applied on all of the output, which results in the flood of printk when using tp_printk. Unfolding event_trigger_unlock_commit_regs() into trace_event_buffer_commit(), so the filters can be applied on every output. Link: https://lkml.kernel.org/r/20210814034538.8428-1-kernelfans@gmail.com Cc: stable@vger.kernel.org Fixes: 0daa2302 ("tracing: Add tp_printk cmdline to have tracepoints go to printk()") Signed-off-by:
Pingfan Liu <kernelfans@gmail.com> Signed-off-by:
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- 12 Aug, 2021 6 commits
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Steven Rostedt (VMware) authored
The following commands: # echo 'read_max u64 size;' > synthetic_events # echo 'hist:keys=common_pid:count=count:onmax($count).trace(read_max,count)' > events/syscalls/sys_enter_read/trigger Causes: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 4 PID: 1763 Comm: bash Not tainted 5.14.0-rc2-test+ #155 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016 RIP: 0010:strcmp+0xc/0x20 Code: 75 f7 31 c0 0f b6 0c 06 88 0c 02 48 83 c0 01 84 c9 75 f1 4c 89 c0 c3 0f 1f 80 00 00 00 00 31 c0 eb 08 48 83 c0 01 84 d2 74 0f <0f> b6 14 07 3a 14 06 74 ef 19 c0 83 c8 01 c3 31 c0 c3 66 90 48 89 RSP: 0018:ffffb5fdc0963ca8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffffb3a4e040 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff9714c0d0b640 RDI: 0000000000000000 RBP: 0000000000000000 R08: 00000022986b7cde R09: ffffffffb3a4dff8 R10: 0000000000000000 R11: 0000000000000000 R12: ffff9714c50603c8 R13: 0000000000000000 R14: ffff97143fdf9e48 R15: ffff9714c01a2210 FS: 00007f1fa6785740(0000) GS:ffff9714da400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000002d863004 CR4: 00000000001706e0 Call Trace: __find_event_file+0x4e/0x80 action_create+0x6b7/0xeb0 ? kstrdup+0x44/0x60 event_hist_trigger_func+0x1a07/0x2130 trigger_process_regex+0xbd/0x110 event_trigger_write+0x71/0xd0 vfs_write+0xe9/0x310 ksys_write+0x68/0xe0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f1fa6879e87 The problem was the "trace(read_max,count)" where the "count" should be "$count" as "onmax()" only handles variables (although it really should be able to figure out that "count" is a field of sys_enter_read). But there's a path that does not find the variable and ends up passing a NULL for the event, which ends up getting passed to "strcmp()". Add a check for NULL to return and error on the command with: # cat error_log hist:syscalls:sys_enter_read: error: Couldn't create or find variable Command: hist:keys=common_pid:count=count:onmax($count).trace(read_max,count) ^ Link: https://lkml.kernel.org/r/20210808003011.4037f8d0@oasis.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: stable@vger.kernel.org Fixes: 50450603 tracing: Add 'onmax' hist trigger action support Reviewed-by: -
Masami Hiramatsu authored
Since the 'bootconfig' command line parameter is handled before parsing the command line, it doesn't use early_param(). But in this case, kernel shows a wrong warning message about it. [ 0.013714] Kernel command line: ro console=ttyS0 bootconfig console=tty0 [ 0.013741] Unknown command line parameters: bootconfig To suppress this message, add a dummy handler for 'bootconfig'. Link: https://lkml.kernel.org/r/162812945097.77369.1849780946468010448.stgit@devnote2 Fixes: 86d1919a ("init: print out unknown kernel parameters") Reviewed-by:
Andrew Halaney <ahalaney@redhat.com> Signed-off-by:
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Lukas Bulwahn authored
Commit 2860cd8a ("livepatch: Use the default ftrace_ops instead of REGS when ARGS is available") intends to enable config LIVEPATCH when ftrace with ARGS is available. However, the chain of configs to enable LIVEPATCH is incomplete, as HAVE_DYNAMIC_FTRACE_WITH_ARGS is available, but the definition of DYNAMIC_FTRACE_WITH_ARGS, combining DYNAMIC_FTRACE and HAVE_DYNAMIC_FTRACE_WITH_ARGS, needed to enable LIVEPATCH, is missing in the commit. Fortunately, ./scripts/checkkconfigsymbols.py detects this and warns: DYNAMIC_FTRACE_WITH_ARGS Referencing files: kernel/livepatch/Kconfig So, define the config DYNAMIC_FTRACE_WITH_ARGS analogously to the already existing similar configs, DYNAMIC_FTRACE_WITH_REGS and DYNAMIC_FTRACE_WITH_DIRECT_CALLS, in ./kernel/trace/Kconfig to connect the chain of configs. Link: https://lore.kernel.org/kernel-janitors/CAKXUXMwT2zS9fgyQHKUUiqo8ynZBdx2UEUu1WnV_q0OCmknqhw@mail.gmail.com/ Link: https://lkml.kernel.org/r/20210806195027.16808-1-lukas.bulwahn@gmail.com Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Miroslav Benes <mbenes@suse.cz> Cc: stable@vger.kernel.org Fixes: 2860cd8a ("livepatch: Use the default ftrace_ops instead of REGS when ARGS is available") Signed-off-by:
Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by:
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Daniel Bristot de Oliveira authored
When using osnoise/timerlat with stop tracing, sometimes it is not clear in which CPU the stop condition was hit, mainly when using some extra events. Print a message informing in which CPU the trace stopped, like in the example below: <idle>-0 [006] d.h. 2932.676616: #1672599 context irq timer_latency 34689 ns <idle>-0 [006] dNh. 2932.676618: irq_noise: local_timer:236 start 2932.676615639 duration 2391 ns <idle>-0 [006] dNh. 2932.676620: irq_noise: virtio0-output.0:47 start 2932.676620180 duration 86 ns <idle>-0 [003] d.h. 2932.676621: #1673374 context irq timer_latency 1200 ns <idle>-0 [006] d... 2932.676623: thread_noise: swapper/6:0 start 2932.676615964 duration 4339 ns <idle>-0 [003] dNh. 2932.676623: irq_noise: local_timer:236 start 2932.676620597 duration 1881 ns <idle>-0 [006] d... 2932.676623: sched_switch: prev_comm=swapper/6 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=timerlat/6 next_pid=852 next_prio=4 timerlat/6-852 [006] .... 2932.676623: #1672599 context thread timer_latency 41931 ns <idle>-0 [003] d... 2932.676623: thread_noise: swapper/3:0 start 2932.676620854 duration 880 ns <idle>-0 [003] d... 2932.676624: sched_switch: prev_comm=swapper/3 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=timerlat/3 next_pid=849 next_prio=4 timerlat/6-852 [006] .... 2932.676624: timerlat_main: stop tracing hit on cpu 6 timerlat/3-849 [003] .... 2932.676624: #1673374 context thread timer_latency 4310 ns Link: https://lkml.kernel.org/r/b30a0d7542adba019185f44ee648e60e14923b11.1626598844.git.bristot@kernel.org Cc: Tom Zanussi <zanussi@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: -
Daniel Bristot de Oliveira authored
Some extra flags are printed to the trace header when using the PREEMPT_RT config. The extra flags are: need-resched-lazy, preempt-lazy-depth, and migrate-disable. Without printing these fields, the timerlat specific fields are shifted by three positions, for example: # tracer: timerlat # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # || / # |||| ACTIVATION # TASK-PID CPU# |||| TIMESTAMP ID CONTEXT LATENCY # | | | |||| | | | | <idle>-0 [000] d..h... 3279.798871: #1 context irq timer_latency 830 ns <...>-807 [000] ....... 3279.798881: #1 context thread timer_latency 11301 ns Add a new header for timerlat with the missing fields, to be used when the PREEMPT_RT is enabled. Link: https://lkml.kernel.org/r/babb83529a3211bd0805be0b8c21608230202c55.1626598844.git.bristot@kernel.org Cc: Tom Zanussi <zanussi@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: -
Daniel Bristot de Oliveira authored
Some extra flags are printed to the trace header when using the PREEMPT_RT config. The extra flags are: need-resched-lazy, preempt-lazy-depth, and migrate-disable. Without printing these fields, the osnoise specific fields are shifted by three positions, for example: # tracer: osnoise # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth MAX # || / SINGLE Interference counters: # |||| RUNTIME NOISE %% OF CPU NOISE +-----------------------------+ # TASK-PID CPU# |||| TIMESTAMP IN US IN US AVAILABLE IN US HW NMI IRQ SIRQ THREAD # | | | |||| | | | | | | | | | | <...>-741 [000] ....... 1105.690909: 1000000 234 99.97660 36 21 0 1001 22 3 <...>-742 [001] ....... 1105.691923: 1000000 281 99.97190 197 7 0 1012 35 14 <...>-743 [002] ....... 1105.691958: 1000000 1324 99.86760 118 11 0 1016 155 143 <...>-744 [003] ....... 1105.691998: 1000000 109 99.98910 21 4 0 1004 33 7 <...>-745 [004] ....... 1105.692015: 1000000 2023 99.79770 97 37 0 1023 52 18 Add a new header for osnoise with the missing fields, to be used when the PREEMPT_RT is enabled. Link: https://lkml.kernel.org/r/1f03289d2a51fde5a58c2e7def063dc630820ad1.1626598844.git.bristot@kernel.org Cc: Tom Zanussi <zanussi@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by:
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- 06 Aug, 2021 1 commit
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Mathieu Desnoyers authored
State transitions from 1->0->1 and N->2->1 callbacks require RCU synchronization. Rather than performing the RCU synchronization every time the state change occurs, which is quite slow when many tracepoints are registered in batch, instead keep a snapshot of the RCU state on the most recent transitions which belong to a chain, and conditionally wait for a grace period on the last transition of the chain if one g.p. has not elapsed since the last snapshot. This applies to both RCU and SRCU. This brings the performance regression caused by commit 231264d6 ("Fix: tracepoint: static call function vs data state mismatch") back to what it was originally. Before this commit: # trace-cmd start -e all # time trace-cmd start -p nop real 0m10.593s user 0m0.017s sys 0m0.259s After this commit: # trace-cmd start -e all # time trace-cmd start -p nop real 0m0.878s user 0m0.000s sys 0m0.103s Link: https://lkml.kernel.org/r/20210805192954.30688-1-mathieu.desnoyers@efficios.com Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.org/ Cc: stable@vger.kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Stefan Metzmacher <metze@samba.org> Fixes: 231264d6 ("Fix: tracepoint: static call function vs data state mismatch") Signed-off-by:
Paul E. McKenney <paulmck@kernel.org> Signed-off-by:
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- 05 Aug, 2021 3 commits
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Mathieu Desnoyers authored
On a 1->0->1 callbacks transition, there is an issue with the new callback using the old callback's data. Considering __DO_TRACE_CALL: do { \ struct tracepoint_func *it_func_ptr; \ void *__data; \ it_func_ptr = \ rcu_dereference_raw((&__tracepoint_##name)->funcs); \ if (it_func_ptr) { \ __data = (it_func_ptr)->data; \ ----> [ delayed here on one CPU (e.g. vcpu preempted by the host) ] static_call(tp_func_##name)(__data, args); \ } \ } while (0) It has loaded the tp->funcs of the old callback, so it will try to use the old data. This can be fixed by adding a RCU sync anywhere in the 1->0->1 transition chain. On a N->2->1 transition, we need an rcu-sync because you may have a sequence of 3->2->1 (or 1->2->1) where the element 0 data is unchanged between 2->1, but was changed from 3->2 (or from 1->2), which may be observed by the static call. This can be fixed by adding an unconditional RCU sync in transition 2->1. Note, this fixes a correctness issue at the cost of adding a tremendous performance regression to the disabling of tracepoints. Before this commit: # trace-cmd start -e all # time trace-cmd start -p nop real 0m0.778s user 0m0.000s sys 0m0.061s After this commit: # trace-cmd start -e all # time trace-cmd start -p nop real 0m10.593s user 0m0.017s sys 0m0.259s A follow up fix will introduce a more lightweight scheme based on RCU get_state and cond_sync, that will return the performance back to what it was. As both this change and the lightweight versions are complex on their own, for bisecting any issues that this may cause, they are kept as two separate changes. Link: https://lkml.kernel.org/r/20210805132717.23813-3-mathieu.desnoyers@efficios.com Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.org/ Cc: stable@vger.kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Stefan Metzmacher <metze@samba.org> Fixes: d25e37d8 ("tracepoint: Optimize using static_call()") Signed-off-by: -
Mathieu Desnoyers authored
On transition from 2->1 callees, we should be comparing .data rather than .func, because the same callback can be registered twice with different data, and what we care about here is that the data of array element 0 is unchanged to skip rcu sync. Link: https://lkml.kernel.org/r/20210805132717.23813-2-mathieu.desnoyers@efficios.com Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.org/ Cc: stable@vger.kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Stefan Metzmacher <metze@samba.org> Fixes: 547305a6 ("tracepoint: Fix out of sync data passing by static caller") Signed-off-by:
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Steven Rostedt (VMware) authored
The hardware latency detector (hwlat) has a mode that it runs one thread across CPUs. The logic to move from the currently running CPU to the next one in the list does a smp_processor_id() to find where it currently is. Unfortunately, it's done with preemption enabled, and this triggers a warning for using smp_processor_id() in a preempt enabled section. As it is only using smp_processor_id() to get information on where it currently is in order to simply move it to the next CPU, it doesn't really care if it got moved in the mean time. It will simply balance out later if such a case arises. Switch smp_processor_id() to raw_smp_processor_id() to quiet that warning. Link: https://lkml.kernel.org/r/20210804141848.79edadc0@oasis.local.homeAcked-by:
Daniel Bristot de Oliveira <bristot@redhat.com> Fixes: 8fa826b7 ("trace/hwlat: Implement the mode config option") Signed-off-by:
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