| get_cyclecount.9 (88974) | get_cyclecount.9 (89193) |
|---|---|
| 1.\" Copyright (c) 2000 Mark R V Murray 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 8 unchanged lines hidden (view full) --- 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" | 1.\" Copyright (c) 2000 Mark R V Murray 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 8 unchanged lines hidden (view full) --- 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" |
| 25.\" $FreeBSD: head/share/man/man9/get_cyclecount.9 88974 2002-01-06 23:56:12Z davidc $ | 25.\" $FreeBSD: head/share/man/man9/get_cyclecount.9 89193 2002-01-10 10:48:39Z ru $ |
| 26.\" 27.Dd November 20, 2000 | 26.\" 27.Dd November 20, 2000 |
| 28.Dt GET_CYCLECOUNTER 9 | 28.Dt GET_CYCLECOUNT 9 |
| 29.Os 30.Sh NAME 31.Nm get_cyclecount 32.Nd get the CPU's fast counter register contents 33.Sh SYNOPSIS 34.In sys/param.h 35.In machine/cpufunc.h 36.In machine/cpu.h 37.Ft u_int64_t 38.Fn get_cyclecount "void" 39.Sh DESCRIPTION 40The 41.Fn get_cyclecount | 29.Os 30.Sh NAME 31.Nm get_cyclecount 32.Nd get the CPU's fast counter register contents 33.Sh SYNOPSIS 34.In sys/param.h 35.In machine/cpufunc.h 36.In machine/cpu.h 37.Ft u_int64_t 38.Fn get_cyclecount "void" 39.Sh DESCRIPTION 40The 41.Fn get_cyclecount |
| 42functon uses a register | 42function uses a register |
| 43available in most modern CPUs 44to return a value 45that is monotonically increasing 46inside each CPU. 47.Pp | 43available in most modern CPUs 44to return a value 45that is monotonically increasing 46inside each CPU. 47.Pp |
| 48In SMP systems, | 48On SMP systems, |
| 49there will be a number of 50separate monotonic sequences, 51one for each CPU running. 52The value in the SMP case is 53selected from one of these sequences, 54dependent on which CPU 55was scheduled to service the request. 56.Pp | 49there will be a number of 50separate monotonic sequences, 51one for each CPU running. 52The value in the SMP case is 53selected from one of these sequences, 54dependent on which CPU 55was scheduled to service the request. 56.Pp |
| 57The speed and maximum value | 57The speed and the maximum value |
| 58of each counter 59is CPU-dependent. 60Some CPUs 61(such as the 62.Tn Intel 6380386 and 80486) 64do not have such a register, 65so --- 34 unchanged lines hidden --- | 58of each counter 59is CPU-dependent. 60Some CPUs 61(such as the 62.Tn Intel 6380386 and 80486) 64do not have such a register, 65so --- 34 unchanged lines hidden --- |