| Title: | DIGITAL UNIX (FORMERLY KNOWN AS DEC OSF/1) |
| Notice: | Welcome to the Digital UNIX Conference |
| Moderator: | SMURF::DENHAM |
| Created: | Thu Mar 16 1995 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 10068 |
| Total number of notes: | 35879 |
Hi!
Customer asked me some question about "time" command, they did a
performance test on DEC's alphaStation 500/333 and HP's C160. The
result of performance test is the following:
HP C160 (128MB,2GB) AlphaStation 500/333(128MB,2GB)
realtime 43.51 33.0
user 26.26 29.6
sys 0.51 0.4
The customer asked why HP's realtime > DEC's but HP's user < DEC's?
What's realtime,user,sys means?
arthur
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 9151.1 | SMURF::DENHAM | Digital UNIX Kernel | Wed Mar 12 1997 21:19 | 7 | |
Realtime means elapsed or wall-clock time.
User means time spent in user mode running application or
library code.
System means time spent in kernel mode doing system calls
or page faults and the like.
| |||||
| 9151.2 | HGOM11::ARTHURWANG | Thu Mar 13 1997 01:16 | 7 | ||
Hello:
is that means realtime = user + system?
pls tell me the relationship about realtime,user,system.
thanks!
arthur
| |||||
| 9151.3 | real time = user + sys + wait | namix.fno.dec.com::jpt | FIS and Chips | Thu Mar 13 1997 03:14 | 15 |
No, realtime is NIT same as User+Sys. User+Sys is same as CPU time used, realtime is how long it takes for the command from start to exit. Realtime is more or less same as User+Sys+Wait meaning that if for example application waits for I/O to complete, it will be added to "Wall Clock Time" but not measured by System or User time. Also, if you have for example workstation, the Windowing Interface can "hog" some CPU time causing it to compete from available time with real life application, and that causes increase of realtime as application must wait other services to complete. -jari | |||||