158550067SMark Murray.\" Copyright (c) 2000 Mark R V Murray 258550067SMark Murray.\" All rights reserved. 358550067SMark Murray.\" 458550067SMark Murray.\" Redistribution and use in source and binary forms, with or without 558550067SMark Murray.\" modification, are permitted provided that the following conditions 658550067SMark Murray.\" are met: 758550067SMark Murray.\" 1. Redistributions of source code must retain the above copyright 858550067SMark Murray.\" notice, this list of conditions and the following disclaimer. 958550067SMark Murray.\" 2. Redistributions in binary form must reproduce the above copyright 1058550067SMark Murray.\" notice, this list of conditions and the following disclaimer in the 1158550067SMark Murray.\" documentation and/or other materials provided with the distribution. 1258550067SMark Murray.\" 1358550067SMark Murray.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1458550067SMark Murray.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1558550067SMark Murray.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1658550067SMark Murray.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1758550067SMark Murray.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1858550067SMark Murray.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 1958550067SMark Murray.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2058550067SMark Murray.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2158550067SMark Murray.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2258550067SMark Murray.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2358550067SMark Murray.\" SUCH DAMAGE. 2458550067SMark Murray.\" 2558550067SMark Murray.\" $FreeBSD$ 2658550067SMark Murray.\" 2758550067SMark Murray.Dd November 20, 2000 28ae9fd628SRuslan Ermilov.Dt GET_CYCLECOUNTER 9 2958550067SMark Murray.Os 3058550067SMark Murray.Sh NAME 3158550067SMark Murray.Nm get_cyclecounter 3258550067SMark Murray.Nd get the CPU's fast counter register contents 3358550067SMark Murray.Sh SYNOPSIS 3458550067SMark Murray.Fd #include <sys/types.h> 3558550067SMark Murray.Fd #include <machine/cpu.h> 3658550067SMark Murray.Ft u_int64_t 3758550067SMark Murray.Fn get_cyclecounter "void" 3858550067SMark Murray.Sh DESCRIPTION 3958550067SMark MurrayThe 4058550067SMark Murray.Fn get_cyclecounter 4158550067SMark Murrayfuncton uses a register 4258550067SMark Murrayavailable in most modern CPUs 4358550067SMark Murrayto return a value 4458550067SMark Murraythat is monotonically increasing 4558550067SMark Murrayinside each CPU. 4658550067SMark Murray.Pp 4758550067SMark MurrayIn SMP systems, 4858550067SMark Murraythere will be a number of 4958550067SMark Murrayseparate monotonic sequences, 5058550067SMark Murrayone for each CPU running. 5158550067SMark MurrayThe value in the SMP case is 5258550067SMark Murrayselected from one of these sequences, 5358550067SMark Murraydependent on which CPU 5458550067SMark Murraywas scheduled to service the request. 5558550067SMark Murray.Pp 5658550067SMark MurrayThe speed and maximum value 5758550067SMark Murrayof each counter 5858550067SMark Murrayis CPU-dependant. 5958550067SMark MurraySome CPUs 6058550067SMark Murray(such as the 6158550067SMark Murray.Tn Intel 6258550067SMark Murray80386 and 80486) 6358550067SMark Murraydo not have such a register, 6458550067SMark Murrayso 6558550067SMark Murray.Fn get_cyclecounter 6658550067SMark Murrayon these platforms 6758550067SMark Murrayreturns the number of nanoseconds 6858550067SMark Murrayrepresented by the 6958550067SMark Murraystructure returned by 7058550067SMark Murray.Xr nanotime 9 . 7158550067SMark Murray.Pp 7258550067SMark MurrayThe 7358550067SMark Murray.Tn Pentium 7458550067SMark Murrayprocessors all use the 7558550067SMark Murray.Li TSC 7658550067SMark Murrayregister. 7758550067SMark Murray.Pp 7858550067SMark MurrayThe 79ae9fd628SRuslan Ermilov.Tn Alpha 80ae9fd628SRuslan Ermilovprocessors use the 8158550067SMark Murray.Li PCC 8258550067SMark Murrayregister. 8358550067SMark Murray.Pp 8458550067SMark MurrayThe 8558550067SMark Murray.Tn IA64 8658550067SMark Murrayprocessors use the 8758550067SMark Murray.Li AR.ITC 8858550067SMark Murrayregister. 8958550067SMark Murray.Sh SEE ALSO 9058550067SMark Murray.Xr nanotime 9 9158550067SMark Murray.Sh HISTORY 9258550067SMark MurrayThe 93ae9fd628SRuslan Ermilov.Fn get_cyclecounter 9458550067SMark Murrayfunction first appeared in 95ae9fd628SRuslan Ermilov.Fx 5.0 . 9658550067SMark Murray.Sh AUTHORS 9758550067SMark MurrayThis manual page was written by 9858550067SMark Murray.An Mark Murray Aq markm@FreeBSD.org . 99