Talk:Load (computing): Difference between revisions

Revision as of 07:08, 15 October 2012

Latest revision as of 13:05, 5 February 2024

(12 intermediate revisions by 10 users not shown)

Line 1:

{{Talk header}}

{{WikiProject banner shell|class=Start|

{{WikiProject Computing|importance=}}

}}

== Waiting, states, calculations ==

Line 160 ⟶ 163:

# 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 0under 1.700 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.

--[[User:Grumpyland|-Grumps]] ([[User talk:Grumpyland|talk]]) 06:50, 15 October 2012 (UTC)

== Confusion on Hz definition ==

"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). <span style="font-size: smaller;" class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/69.84.133.248|69.84.133.248]] ([[User talk:69.84.133.248|talk]]) 15:24, 25 April 2013 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

== Notes ==

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.~~ <small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/86.124.79.201|86.124.79.201]] ([[User talk:86.124.79.201|talk]]) 07:26, 14 March 2015 (UTC)</small><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

There is no error.

[[Special:Contributions/194.166.103.157|194.166.103.157]] ([[User talk:194.166.103.157|talk]]) 21:41, 17 March 2015 (UTC)

== definition is ridiculous ==

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. <b>...&nbsp;</b><span style="background-color: #11cbc4;width:52px;height:16px;font-size:12px;p{text-align:center}">[[user:avriette|jane avriette]]:[[user_talk:avriette|talk]]</span> 19:15, 28 October 2015 (UTC)

: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 supported[[User:Andrewcrawford|<span style="color:LightBlue;">Andrewcrawford</span>]] ([[User talk:Andrewcrawford|<small>talk</small>]] - [[Special:Contributions/Andrewcrawford|<small>contrib</small>]]) 17:24, 29 October 2015 (UTC)

::these "obscure policies" are why i stopped editing. <b>...&nbsp;</b><span style="background-color: #11cbc4;width:52px;height:16px;font-size:12px;p{text-align:center}">[[user:avriette|jane avriette]]:[[user_talk:avriette|talk]]</span> 20:18, 18 November 2015 (UTC)