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Network Working Group Request for Comments: 546 NIC: 17792

B. Thomas BBN-TENEX 10 August 1973

TENEX Load Averages for July 1973

This RFC presents utilization data for the BBN and ISI TENEX systems which may be of interest to the network community. The graph on page 4 summarizes the load Hosts during the work week for the month hourly load average [1] for each site is day; the time of day is Eastern Daylight at the BBN-TENEX and USC-ISI of July 1973. The weekday plotted versus the time of Time.

Interpreting data such as this is tricky business. However, it is difficult to resist making the following observations: 1. The shapes of the BBN and furthermore, there is no that the user populations habits and are acclimated ISI skew for to curves between the two the same are approximately the same; the curves. This suggests systems have similar working time zone.

2. The significant features of both correlated with "normal events" East Coast time,suggesting that influenced most strongly by such

curves appear to be strongly in the day of a user living on the load at both sites is users:

a. the load begins to increase between 7-8 a.m. EDT as users begin their daily computing; b. it dips between 10-11 a.m. EDT (smoothed to a smaller rate of increase in the ISI curve) as users take their coffee break; c. the load peaks sharply between 1-2 p.m. EDT as users return from lunch to resume their computing; d. it decreases as the afternoon continues and as users go home from work; e. it reaches a local minimum between 6-7 p.m. EDT (minimum not present in ISI curve) when most people eat dinner; f. it increases to an evening peak between 9-10 p.m. EDT as some users come back from dinner and after dinner activities to resume their computing.

Thomas

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RFC 546

TENEX Load Averages for July 1973

10 August 1973

3. The curve for ISI is smoother than the one for break" dip appears only as a decrease in slope; and evening peak are completely smoothed out. probably due to the influence of the West Coast machine. 4.

BBN: the "coffee the dinner break This smoothing is users of the ISI

During July the BBN system was more heavily loaded than the ISI system. Since the data collected did not include the number of active jobs it is not possible to determine from the data whether BBN had more users or just more demanding users.

The data presented on the graph is available as a side effect of the RSEXEC system. The server programs for the RSEXEC system (RSSER programs) communicate regularly with one another exchanging status information. The RSSER program at each site maintains a (dynamic) data base of the information it collects from the RSSER programs at other sites. The NETLOAD command of the TENEX EXEC, as well as many RSEXEC commands, makes use of information in that database. The raw data for BBN and ISI [2] load curves (as well other TENEX sites that run RSSER) was collected by a creates daily load information files by periodically minutes) reading load average data from the data base RSSER. The monthly summary was produced by a program daily data files. as data for the program which (every 3 maintained by that analyzes

[The following graph is also available in .PS and .PDF format.]

Thomas

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RFC 546

TENEX Load Averages for July 1973

10 August 1973

Weekday Hourly Load Averages July 1973 ^ B BBN-TENEX | I ISI-TENEX 10 + | | B | + | | | + B Load | Avg. | B | I + | | | * + I | | B IB | B 5+ | | B I | I + I | | | B + I B | B | I | I IB B + I | I B I | B | B IB +I I I | B* B | **II* | BB ---+--+-----------+-----------+-----------+-----------+> | 0-1 AM 6-7 AM 12-1 PM 6-7 PM 12 (midnight) (noon) (midnight) Time of Day (Eastern Daylight Time)

Thomas

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RFC 546

TENEX Load Averages for July 1973

10 August 1973

Endnotes [1] The TENEX load average is a measure of CPU demand. The load average is an average of the number of runable processes over a given time period. For example, an hourly load average of 10 would mean that (for a single CPU system) at any time during that hour one could expect to see 1 process running and 9 others ready to run (i.e., not blocked for I/O) waiting for the CPU. [2] The data for BBN and ISI was chosen for presentation in this RFC because the BBN and ISI TENEXs are two of the major time-sharing service hosts on the network.

[ This RFC was put into machine readable form for entry ] [ into the online RFC archives by Jim Larson 3/98 ]

Thomas

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