NetBSD/usr.sbin/lockstat/lockstat.8

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.\" $NetBSD: lockstat.8,v 1.9 2009/03/21 13:02:19 ad Exp $
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Andrew Doran.
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.Dd March 21, 2009
.Dt LOCKSTAT 8
.Os
.Sh NAME
.Nm lockstat
.Nd display kernel locking statistics
.Sh SYNOPSIS
.Nm
.Op Fl ceflMmpstx
.Op Fl b Ar nbuf
.Op Fl E Ar event
.Op Fl F Ar func
.Op Fl L Ar lock
.Op Fl N Ar nlist
.Op Fl o Ar file
.Op Fl T Ar type
.Ar command ...
.Sh DESCRIPTION
The
.Nm
command enables system wide tracing of kernel lock events, executes
the specified command, and when finished reports statistics to the user.
.Pp
Tracing may be ended early by sending
.Dv SIGINT
(Ctrl-C) to the process being executed by lockstat.
.Pp
The
.Nm lockstat
pseudo-device
driver must be present in the kernel, and the
.Nm
command may only be used by the root user.
.Pp
The options are as follows:
.Bl -tag -width wellhello
.It Fl b Ar nbuf
Adjust the number of trace buffers allocated by the kernel to
.Ar nbuf .
.It Fl c
Report percentage of total events by count, and sort the output by number
of events.
The default is to key on event timings.
.It Fl E Ar event
Limit tracing to one type of event.
Use the
.Fl e
option to list valid events.
.It Fl e
List valid event types for the
.Fl E
option and exit.
.It Fl F Ar func
Limit tracing to locking operations performed within the specified function.
.Ar func
must be the name of a valid function in the kernel.
.It Fl f
Trace only by calling functions; do not report on individual locks.
.It Fl L Ar lock
Limit tracing to one lock.
.Ar lock
may either be the name of a lock object in the kernel, or a kernel virtual
address.
.It Fl l
Trace only by lock; do not report on calling functions.
.It Fl M
Merge lock addresses within unique objects.
.It Fl m
Merge call sites within unique functions.
.It Fl N Ar nlist
Extract symbol information from the
.Ar nlist
file.
.It Fl o Ar file
Send output to the file named by
.Ar file ,
instead of the standard output (the default).
.It Fl p
Show the average number of events and time spent per CPU.
The default is to show the total values.
May be used in conjunction with the
.Fl s
option.
.It Fl s
Show the average number of events per second, and the average time spent per
second.
The default is to show the total values.
.It Fl T Ar type
Limit tracing to one type of lock.
Use the
.Fl t
option to list valid lock types.
.It Fl t
List valid lock types for the
.Fl T
option and exit.
.It Fl x
Summarize events, and do not report on lock types.
.El
.Sh FILES
.Bl -tag -width /dev/lockstat -compact
.It Pa /dev/lockstat
.Nm
control device
.It Pa /dev/ksyms
namelist
.El
.Sh EXAMPLES
.Bd -literal
# lockstat -L uvm_pageqlock sleep 10
Elapsed time: 10.01 seconds.
-- Adaptive mutex spin
Total% Count Time/ms Lock Caller
------ ------- --------- ---------------------- ------------------------------
100.00 1281 0.78 uvm_pageqlock \*[Lt]all\*[Gt]
39.81 385 0.31 uvm_pageqlock uvm_fault_internal+11cc
30.98 358 0.24 uvm_pageqlock uvm_fault_internal+bb1
28.06 522 0.22 uvm_pageqlock uvm_anfree+132
0.51 5 0.00 uvm_pageqlock ubc_fault+28f
0.20 4 0.00 uvm_pageqlock uvm_fault_internal+12b6
0.18 2 0.00 uvm_pageqlock uao_detach_locked+58
0.11 2 0.00 uvm_pageqlock uvm_fault_internal+7d5
0.08 2 0.00 uvm_pageqlock ufs_balloc_range+160
0.07 1 0.00 uvm_pageqlock uvm_fault_internal+107b
.Ed
.Sh DIAGNOSTICS
.Bl -diag
.It "lockstat: incompatible lockstat interface version"
.Pp
The kernel device driver does not match the version of the
.Nm
command.
.It "lockstat: overflowed available kernel trace buffers"
.Pp
Increase the number of buffers using the
.Fl b
option.
.It "lockstat: ioctl: Invalid argument"
.Pp
The number of trace buffers is outside the minimum and maximum
bounds set by the kernel.
.El
.Sh SEE ALSO
.Xr ps 1 ,
.Xr systat 1 ,
.Xr vmstat 1 ,
.Xr iostat 8 ,
.Xr pstat 8
.Sh HISTORY
The
.Nm
command appeared in
.Nx 4.0 .