Module Name: src Committed By: wiz Date: Sun Mar 5 23:15:35 UTC 2017
Modified Files: src/share/man/man9: disk.9 Log Message: New sentence, new line. Use more macros. Bump date for previous. To generate a diff of this commit: cvs rdiff -u -r1.44 -r1.45 src/share/man/man9/disk.9 Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/share/man/man9/disk.9 diff -u src/share/man/man9/disk.9:1.44 src/share/man/man9/disk.9:1.45 --- src/share/man/man9/disk.9:1.44 Sun Mar 5 23:07:12 2017 +++ src/share/man/man9/disk.9 Sun Mar 5 23:15:35 2017 @@ -1,4 +1,4 @@ -.\" $NetBSD: disk.9,v 1.44 2017/03/05 23:07:12 mlelstv Exp $ +.\" $NetBSD: disk.9,v 1.45 2017/03/05 23:15:35 wiz Exp $ .\" .\" Copyright (c) 1995, 1996 Jason R. Thorpe. .\" All rights reserved. @@ -30,7 +30,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd December 29, 2014 +.Dd March 5, 2017 .Dt DISK 9 .Os .Sh NAME @@ -173,9 +173,11 @@ required. .It Fn disk_wait Disk timings are measured by counting the number of queued requests (wait counter) and requests issued to the hardware (busy counter) -and keeping timestamp when the counters change. The time interval between +and keeping timestamp when the counters change. +The time interval between two changes of a counter is accumulated into a total and also multiplied -by the counter value and the accumulated into a sum. Both values can be +by the counter value and the accumulated into a sum. +Both values can be used to determine how much time is spent in the driver queue or in-flight to the hardware as well as the average number of requests in either state. .Fn disk_wait @@ -183,7 +185,8 @@ increment the disk's wait counter and ha .It Fn disk_busy Decrements the disk's wait counter and increments the disk's .Dq busy counter , -and handles either accumulation. If the wait counter is still zero, it +and handles either accumulation. +If the wait counter is still zero, it is assumed that the driver hasn't been updated to call .Fn disk_wait , then only the values from the busy counter are available. @@ -568,4 +571,4 @@ The .Nx generic disk framework was architected and implemented by .An Jason R. Thorpe -.Aq thor...@netbsd.org . +.Aq Mt thor...@netbsd.org .