diff --git a/share/man/man4/ktr.4 b/share/man/man4/ktr.4 index 730c3ec619a0..175a7ac7e2af 100644 --- a/share/man/man4/ktr.4 +++ b/share/man/man4/ktr.4 @@ -1,210 +1,210 @@ .\" Copyright (c) 2001 John H. Baldwin .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $FreeBSD$ .\" -.Dd October 20, 2012 +.Dd March 26, 2021 .Dt KTR 4 .Os .Sh NAME .Nm ktr .Nd kernel tracing facility .Sh SYNOPSIS .Cd options KTR .Cd options ALQ .Cd options KTR_ALQ .Cd options KTR_COMPILE=(KTR_LOCK|KTR_INTR|KTR_PROC) .Cd options KTR_CPUMASK=0x3 .Cd options KTR_ENTRIES=8192 .Cd options KTR_MASK=(KTR_INTR|KTR_PROC) .Cd options KTR_VERBOSE .Sh DESCRIPTION The .Nm facility allows kernel events to be logged while the kernel executes so that they can be examined later when debugging. The only mandatory option to enable .Nm is .Dq Li options KTR . .Pp The .Dv KTR_ENTRIES option sets the size of the buffer of events. The size of the buffer in the currently running kernel can be found via the sysctl .Va debug.ktr.entries . By default the buffer contains 1024 entries. .Ss Event Masking Event levels can be enabled or disabled to trim excessive and overly verbose logging. First, a mask of events is specified at compile time via the .Dv KTR_COMPILE option to limit which events are actually compiled into the kernel. The default value for this option is for all events to be enabled. .Pp Secondly, the actual events logged while the kernel runs can be further masked via the run time event mask. The .Dv KTR_MASK option sets the default value of the run time event mask. The runtime event mask can also be set by the .Xr loader 8 via the .Va debug.ktr.mask environment variable. It can also be examined and set after booting via the .Va debug.ktr.mask sysctl. By default the run time mask is set to block any tracing. The definitions of the event mask bits can be found in -.In sys/ktr.h . +.In sys/ktr_class.h . .Pp Furthermore, there is a CPU event mask whose default value can be changed via the .Dv KTR_CPUMASK option. When two or more parameters to .Dv KTR_CPUMASK , are used, it is important they are not separated by whitespace. A CPU must have the bit corresponding to its logical id set in this bitmask for events that occur on it to be logged. This mask can be set by the .Xr loader 8 via the .Va debug.ktr.cpumask environment variable. It can also be examined and set after booting via the .Va debug.ktr.cpumask sysctl. By default, only CPUs specified in .Dv KTR_CPUMASK will log events. See .Pa sys/conf/NOTES for more information. .Ss Verbose Mode By default, events are only logged to the internal buffer for examination later, but if the verbose flag is set then they are dumped to the kernel console as well. This flag can also be set from the loader via the .Va debug.ktr.verbose environment variable, or it can be examined and set after booting via the .Va debug.ktr.verbose sysctl. If the flag is set to zero, which is the default, then verbose output is disabled. If the flag is set to one, then the contents of the log message and the CPU number are printed to the kernel console. If the flag is greater than one, then the filename and line number of the event are output to the console in addition to the log message and the CPU number. The .Dv KTR_VERBOSE option sets the flag to one. .Ss Examining the Events The KTR buffer can be examined from within .Xr ddb 4 via the .Ic show ktr Op Cm /vV command. This command displays the contents of the trace buffer one page at a time. At the .Dq Li --more-- prompt, the Enter key displays one more entry and prompts again. The spacebar displays another page of entries. Any other key quits. By default the timestamp, filename, and line number are not displayed with each log entry. If the .Cm /v modifier is specified, then they are displayed in addition to the normal output. If the .Cm /V modifier is specified, then just the timestamp is displayed in addition to the normal output. Note that the events are displayed in reverse chronological order. That is, the most recent events are displayed first. .Ss Logging ktr to Disk The .Dv KTR_ALQ option can be used to log .Nm entries to disk for post analysis using the .Xr ktrdump 8 utility. This option depends on the .Dv ALQ option. Due to the potentially high volume of trace messages the trace mask should be selected carefully. This feature is configured through a group of sysctls. .Bl -tag -width ".Va debug.ktr.alq_enable" .It Va debug.ktr.alq_file displays or sets the file that .Nm will log to. By default its value is .Pa /tmp/ktr.out . If the file name is changed while .Nm is enabled it will not take effect until the next invocation. .It Va debug.ktr.alq_enable enables logging of .Nm entries to disk if it is set to one. Setting this to 0 will terminate logging to disk and revert to logging to the normal ktr ring buffer. Data is not sent to the ring buffer while logging to disk. .It Va debug.ktr.alq_max is the maximum number of entries that will be recorded to disk, or 0 for infinite. This is helpful for limiting the number of particularly high frequency entries that are recorded. .It Va debug.ktr.alq_depth determines the number of entries in the write buffer. This is the buffer that holds entries before they are written to disk and defaults to the value of the .Dv KTR_ENTRIES option. .It Va debug.ktr.alq_failed records the number of times we failed to write an entry due to overflowing the write buffer. This may happen if the frequency of the logged .Nm messages outpaces the depth of the queue. .It Va debug.ktr.alq_cnt records the number of entries that have currently been written to disk. .El .Sh SEE ALSO .Xr ktrdump 8 , .Xr alq 9 , .Xr ktr 9 .Sh HISTORY The KTR kernel tracing facility first appeared in .Bsx 3.0 and was imported into .Fx 5.0 . diff --git a/share/man/man9/ktr.9 b/share/man/man9/ktr.9 index 17af74ff8459..c7f4138b855c 100644 --- a/share/man/man9/ktr.9 +++ b/share/man/man9/ktr.9 @@ -1,161 +1,161 @@ .\" Copyright (c) 2001 John H. Baldwin .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $FreeBSD$ .\" -.Dd November 30, 2008 +.Dd March 26, 2021 .Dt KTR 9 .Os .Sh NAME .Nm CTR0 , CTR1 , CTR2 , CTR3 , CTR4 , CTR5 .Nd kernel tracing facility .Sh SYNOPSIS .In sys/param.h .In sys/ktr.h .Vt "extern int ktr_cpumask" ; .Vt "extern int ktr_entries" ; .Vt "extern int ktr_extend" ; .Vt "extern int ktr_mask" ; .Vt "extern int ktr_verbose" ; .Vt "extern struct ktr_entry ktr_buf[]" ; .Ft void .Fn CTR0 "u_int mask" "char *format" .Ft void .Fn CTR1 "u_int mask" "char *format" "arg1" .Ft void .Fn CTR2 "u_int mask" "char *format" "arg1" "arg2" .Ft void .Fn CTR3 "u_int mask" "char *format" "arg1" "arg2" "arg3" .Ft void .Fn CTR4 "u_int mask" "char *format" "arg1" "arg2" "arg3" "arg4" .Ft void .Fn CTR5 "u_int mask" "char *format" "arg1" "arg2" "arg3" "arg4" "arg5" .Ft void .Fn CTR6 "u_int mask" "char *format" "arg1" "arg2" "arg3" "arg4" "arg5" "arg6" .Sh DESCRIPTION KTR provides a circular buffer of events that can be logged in a .Xr printf 9 style fashion. These events can then be dumped with .Xr ddb 4 , .Xr gdb 1 or .Xr ktrdump 8 . .Pp Events are created and logged in the kernel via the .Dv CTR Ns Ar x macros. The first parameter is a mask of event types .Pq Dv KTR_* defined in -.In sys/ktr.h . +.In sys/ktr_class.h . The event will be logged only if any of the event types specified in .Fa mask are enabled in the global event mask stored in .Va ktr_mask . The .Fa format argument is a .Xr printf 9 style format string used to build the text of the event log message. Following the .Fa format string are zero to five arguments referenced by .Fa format . Each event is logged with a file name and source line number of the originating CTR call, and a timestamp in addition to the log message. .Pp The event is stored in the circular buffer with supplied arguments as is, and formatting is done at the dump time. Do not use pointers to the objects with limited lifetime, for instance, strings, because the pointer may become invalid when buffer is printed. .Pp Note that the different macros differ only in the number of arguments each one takes, as indicated by its name. .Pp The .Va ktr_entries variable contains the number of entries in the .Va ktr_buf array. These variables are mostly useful for post-mortem crash dump tools to locate the base of the circular trace buffer and its length. .Pp The .Va ktr_mask variable contains the run time mask of events to log. .Pp The CPU event mask is stored in the .Va ktr_cpumask variable. .Pp The .Va ktr_verbose variable stores the verbose flag that controls whether events are logged to the console in addition to the event buffer. .Sh EXAMPLES This example demonstrates the use of tracepoints at the .Dv KTR_PROC logging level. .Bd -literal void mi_switch() { ... /* * Pick a new current process and record its start time. */ ... CTR3(KTR_PROC, "mi_switch: old proc %p (pid %d)", p, p->p_pid); ... cpu_switch(); ... CTR3(KTR_PROC, "mi_switch: new proc %p (pid %d)", p, p->p_pid); ... } .Ed .Sh SEE ALSO .Xr ktr 4 , .Xr ktrdump 8 .Sh HISTORY The KTR kernel tracing facility first appeared in .Bsx 3.0 and was imported into .Fx 5.0 . .Sh BUGS Currently there is one global buffer shared among all CPUs. It might be profitable at some point in time to use per-CPU buffers instead so that if one CPU halts or starts spinning, then the log messages it emitted just prior to halting or spinning will not be drowned out by events from the other CPUs. .Pp The arguments given in .Fn CTRx macros are stored as .Vt u_long , so do not pass arguments larger than size of an .Vt u_long type. For example passing 64bit arguments on 32bit architectures will give incorrect results.