| devstat.9 (44519) | devstat.9 (49831) |
|---|---|
| 1.\" 2.\" Copyright (c) 1998, 1999 Kenneth D. Merry. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright --- 11 unchanged lines hidden (view full) --- 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" | 1.\" 2.\" Copyright (c) 1998, 1999 Kenneth D. Merry. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright --- 11 unchanged lines hidden (view full) --- 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" |
| 28.\" $Id: devstat.9,v 1.2 1999/02/10 00:02:53 ken Exp $ | 28.\" $Id: devstat.9,v 1.3 1999/03/06 17:10:15 bde Exp $ |
| 29.\" 30.Dd May 22, 1998 31.Dt DEVSTAT 9 32.Os FreeBSD 3.0 33.Sh NAME 34.Nm devstat 35.Nd kernel interface for keeping device statistics 36.Sh SYNOPSIS --- 332 unchanged lines hidden (view full) --- 369.Xr rpc.rstatd 8 , 370.Xr vmstat 8 371.Sh HISTORY 372The 373.Nm 374statistics system appeared in 375.Fx 3.0 . 376.Sh AUTHORS | 29.\" 30.Dd May 22, 1998 31.Dt DEVSTAT 9 32.Os FreeBSD 3.0 33.Sh NAME 34.Nm devstat 35.Nd kernel interface for keeping device statistics 36.Sh SYNOPSIS --- 332 unchanged lines hidden (view full) --- 369.Xr rpc.rstatd 8 , 370.Xr vmstat 8 371.Sh HISTORY 372The 373.Nm 374statistics system appeared in 375.Fx 3.0 . 376.Sh AUTHORS |
| 377Kenneth Merry 378.Aq ken@FreeBSD.ORG | 377.An Kenneth Merry Aq ken@FreeBSD.org |
| 379.Sh BUGS 380There may be a need for 381.Fn spl 382protection around some of the 383.Nm 384list manipulation code to insure, for example, that the list of devices 385is not changed while someone is fetching the 386.Va kern.devstat.all 387.Nm sysctl 388variable. 389.Pp 390It is impossible with the current 391.Nm 392architecture to accurately measure time per transaction. The only feasible 393way to accurately measure time per transaction would be to record a 394timestamp for every transaction. This measurement is probably not 395worthwhile for most people as it would adversely affect the performance of 396the system and cost space to store the timestamps for individual 397transactions. | 378.Sh BUGS 379There may be a need for 380.Fn spl 381protection around some of the 382.Nm 383list manipulation code to insure, for example, that the list of devices 384is not changed while someone is fetching the 385.Va kern.devstat.all 386.Nm sysctl 387variable. 388.Pp 389It is impossible with the current 390.Nm 391architecture to accurately measure time per transaction. The only feasible 392way to accurately measure time per transaction would be to record a 393timestamp for every transaction. This measurement is probably not 394worthwhile for most people as it would adversely affect the performance of 395the system and cost space to store the timestamps for individual 396transactions. |