Talk:Load (computing)

message: Is there a contradiction in this article?
In the "Calculating Load Average" section, it states:
  each process that is using the CPU or waiting for disk activity
  adds 1 to the load number
In the "Important things to note" section, it states:
  processes which are awaiting I/O, "sleeping" or "blocked" don't
  contribute to load average
Doesn't "waiting for disk activity" mean that a process is blocked waiting for disk I/O?
In general, it would be very helpful if this article explained in which "states" a process contributes to the load number.
Beric 21:45, 22 February 2006 (UTC)
thread_title:  Waiting, states, calculations 

message: The author states that "On Microsoft Windows PC systems, the system load is given as an instantaneous percentage of CPU utilization." That's not possible, there is no CPU "speedometer" on any processor chip set that I know of. An operating system can only recognize two basic states: idle (0% utilization) or not idle (100% utilization). To report a utilization between 0% and 100% requires that it average the two basic states over some time period. Most operating systems do this by sampling the current state during each clock interrupt and incrementing one of the two state counters (most operating systems also have sub-counters under Not Idle such as Wait I/O in UNIX or processing nested interrupts). The utilization that is then reported is the difference between the counters over some sampling interval divided by the total samples during the interval and that is what is reported as utilization. As for what time interval Windows utilities such as perfmon and the Logs & Alerts Service use I have no clue.—Preceding unsigned comment added by 171.159.64.10 (talk • contribs) 13:01, 9 June 2006
* Some chips scale frequency now, but your point is still 99% correct. 128.135.99.80 19:57, 7 September 2006 (UTC)
replies: text: So you're just complaining about how it's worded?--Bobby D. DS. 23:17, 29 October 2006 (UTC)

text: I suspect part of the problem is that the term "load average" is very well defined, but the term "load" is vague at best.  This article is currently mostly about the Unix load average, and not about "Load (computing)".  Whether we should change this article to be more general, or simply rename it to Load average and create a new Load (computing) stub with the rest of the content, I dunno. --DragonHawk 02:06, 4 January 2007 (UTC)
thread_title:  Instantaneous percentage of CPU utilization on Windows?!? 

message: The article talks about "each process that is using CPU".  I think it's more common to talk about "each job", which isn't necessarily synonymous.  For example, a process with two threads can count as two jobs. —Preceding unsigned comment added by 86.17.154.122 (talk • contribs) 04:30, 31 July 2006
:I think the problem is that each UNIXoid operating system will use different terms. For example, on Linux your jobs are called "tasks".—Preceding unsigned comment added by 62.31.146.25 (talk • contribs) 11:42, 27 August 2006
don't know about you, guys, but wherever I found the word "job" before (related to something to be executed by a computer, that is)
it referred to a batch file containing some non-interactive stuff to be done in a certain sequence (series or parallel or both).
A job usually contains more processes and has nothing to do with the load average we are talking about here.
—Preceding unsigned comment added by 70.54.202.152 (talk • contribs) 13:07, 1 November 2006
For unix, there are specific meanings to the terms "job" and "process".  A job is in the jobtable, a process is in the process table.  See `jobs` for a list of jobs for the current terminal, and `ps` for a list of process for the current system.  Don't be confused by cron terminology; jobs aren't processes.  --87.194.236.208 (talk) 15:20, 4 May 2008 (UTC)
thread_title:  Processes or jobs? 

message: This page needs to decide if it is about unix (& clones) load averages, or about the concept of computer load.  There isn't currently a page about unix load averages, and most of the unix related stuff here is reasonable enough to start one.  The windows section needs to be expanded or explained.  The "Other Meanings" section would probably be better shifted to their respective pages, or made into separate stub pages.  --CalPaterson (talk) 15:29, 4 May 2008 (UTC)
replies: text: The windows section needs deleted, really. Windows has no use for load averages. 89.240.240.107 (talk) 13:19, 12 May 2008 (UTC)
thread_title:  Unix or windows or both 

message: I just removed a section titled "Load average is not CPU utilization" added by Sp0 a few months ago. The text of the section was:
: Even though the statements in the previous section might suggest that load average is related to CPU utilization because the section relates CPU to load average, load average does not measure CPU utilization of processes. One reason it does not do this is because load averages computations of processes are in a wrong order to relate to trend information of CPU utilization. In other words, the calculations and numbers directly produced by load averages do not compute numbers in an order from more CPU intensive to less CPU intensive or vice versa, nor do they give computations of numbers that would give another way that would result in direct information about CPU utilization. In summary, the functions of load average give numbers based on load queue of processes. The next section uses the same reference to suggest that load average is not very important or vital to system performance information until or unless the a system's CPU is heavily loaded to around 100%. Then, at levels close to 100%, load average could be very important or significant to determinacy of system performance; however, this would be because average load numbers give direct information about process queue length not CPU utilization -- which is something they do not give direct information about.
Without making any comment on the accuracy of this information, there are two severe problems with this: First, it is almost completely incomprehensible due to grammatical errors and a generally rambling style. Second, the section existed to contradict the rest of the article. Sp0, if you believe the article is factually inaccurate, the correct response is to edit or replace the existing text to make it accurate, and preferably also to include citations of reliable sources to prevent an edit war. -- Tyler (talk) 18:24, 8 January 2010 (UTC)
thread_title:  "Load average is not CPU utilization" Section 

message: This article has so many sections that are misleading or wrong that I don't even know where to start... Almost want to delete much of it, yet lazy to rewrite...
# Adding to the note by previous user, "Load average is not CPU utilization" is correct. Load average is not necessarily CPU utilization. If the system was hanging on disk all the time, and CPU was hitting high iowait, it's not exactly "utilizing" the CPU. 
# Statements like this is just wrong: "(no processes had to wait for a turn)". We already know processes waited on the minute average, just because we change averages doesn't magically change history. Average does not define minimums and maximums.
# To use the word "overloaded" and "underloaded" is correct but also highly misleading. Your system may not be conceptually underloaded at all even if the system has under 1.00 load average. Loads spike and drop, once again, average does not define minimums and maximums. Whether it's underloaded or not depends on what is running and how it's affecting the system. To give a specific example, let's say we have a voice communication program and every time you say something, it uses more CPU. But your CPU can't handle the increased load and thus sends stuttering messages. So, the communication program overloads your CPU. But you don't talk 100% of the time, so, it may be underloaded most of the time. Then to say your CPU is underloaded but your CPU couldn't handle the communication program is highly confusing.
# "This means that this CPU could have handled all of the work scheduled for the last minute if it were 1.73 times as fast" is also untrue. Load average, once again, is not purely dependent on CPU. That implies that load average only depends on CPU.
---Grumps (talk) 06:50, 15 October 2012 (UTC)
thread_title:  Misleading and wrong... 

message: "On Linux systems, the load-average is not calculated on each clock tick, but driven by a variable value that is based on the Hz frequency setting and tested on each clock tick. (Hz variable is the pulse rate of particular Linux kernel activity. 1Hz is equal to one clock tick; 10ms by default.) Although the Hz value can be configured in some versions of the kernel, it is normally set to 100. The calculation code uses the Hz value to determine the CPU Load calculation frequency. Specifically, the timer.c::calc_load() function will run the algorithm every 5 * Hz, or roughly every five seconds. Following is that function in its entirety:"
The above paragraph in the article is very confusing.
I think it is confusing Hz with the Linux kernel interrupt timer.
>>  1Hz is equal to one clock tick; 10ms by default.
If the definition of hertz is "cycles per second" as defined by the Hertz article on Wikipedia, then how can 1 Hz be 10ms?
1 Hz would be 1 cycle per second, which would mean that the clock ticks once per second.
I think the 10ms is actually referring to the Linux kernel interrupt timer which is normally set to 100, or roughly every 10 ms.
The kernel interrupt will fire 100 times a second.
>> Although the Hz value can be configured in some versions of the kernel, it is normally set to 100.
Huh?  I thought it just said that 1 Hz is equal to one clock tick?
I guess that what it is referring to is the Linux timer interrupt frequency again.
>> Specifically, the timer.c::calc_load() function will run the algorithm every 5 * Hz, or roughly every five seconds.
That makes sense if the Hz value is 1 (one cycle per second).  — Preceding unsigned comment added by 69.84.133.248 (talk) 15:24, 25 April 2013 (UTC)
thread_title:  Confusion on Hz definition 

message: There is currently one note regarding an error in a paper. This should probably be signaled to the
author of that paper instead of sitting on a wiki page. What's also missing is some reasoning behind
the error that was signaled.
Would be nice if the wiki page would recommend a correct reference for a complete description of the
concept.~~  — Preceding unsigned comment added by 86.124.79.201 (talk) 07:26, 14 March 2015 (UTC)
thread_title:  Notes 

message: The term "system load" (the title of this article) cannot be defined using the term itself.
: In UNIX computing, the system load is a measure of the amount of computational work that a computer system performs. The load averagerepresents the average system load over a period of time. It conventionally appears in the form of three numbers which represent the system load during the last one-, five-, and fifteen-minute periods.
This is an unacceptable definition.
I am capable of providing a substantial rewrite to this article and creating one that is much more useful in explaining how this works on Unix systems (and probably the article should be retitled as 'system load' is a dramatically different term on Unix (&Unix-like) systems than it is on mainframe and Windows systems (as well as realtime systems like embedded). I note also that this article has "needed references" since 2010.
As somebody who has been an editor of this fine encyclopedia since 2004, I am hesitant to even bother making these changes as I am aware the piranhas will attack and say "well you cannot just go and edit this thing without sources." I have been a Unix engineer for twenty years and I am a source. You are unlikely to find sources to corroborate things in this article as Unix is a moving target. As kernels in Linux have progressed from 2.2 to 2.4 to 2.6 and the 3 kernels, system load has changed dramatically and how we measure it has changed.
I therefore also feel that the tag demanding this article be better referenced is preposterous. The tag should be removed, and people who have their dander up about sources on this article should perhaps be asked to undander themselves. ... jane avriette:talk 19:15, 28 October 2015 (UTC)
replies: text: I am retired editor but i have made a pledge to provide requests for comments when asked.  Unfortunately the point about references can not be by passed however the definition of references of taggers is generally they do not understand each topic and think that we need 1000 references, but the Wikipedia policy on reference does not say we need lot but for anything written it must be backed up by a reliable third party source. You are quite entitle to rewrite it using your knowledge but you would need to provide a reference that backs up what your saying in this day and age finding reference is not as hard as it was 10 years ago granted this topic will have less references than say a well published subject but there is references. My suggestion is to make a sub test page of the article and then write up your changes how you think the page should be and then request for comment on that as long as it complies with principle standards of Wikipedia then it can not be objected you will find there is some editors who will quote obscure policies to block you but these policies are all derived from the core policies which i can quote later if there is issues. Good luck on the rewrite as it does need a rewrite as with a lot of other articles also if you think the subject matter ie the title is not write then suggest a new one and we can have it moved if supportedAndrewcrawford (talk - contrib) 17:24, 29 October 2015 (UTC)
replies: text: these "obscure policies" are why i stopped editing. ... jane avriette:talk 20:18, 18 November 2015 (UTC)
thread_title:  definition is ridiculous