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Linux load average

 
 
RT
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Posts: n/a
 
      10-29-2004

"Gordon" <(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> On Sat, 30 Oct 2004 18:19:47 +1300, thing wrote:
>
>> One really good use of top.....[snip]

>
> Use top, yes it is command line, but it does give you more than you need
> to know.
>
> A must have when you need/want it.
>


Or you can use gtop or ktop and use your mouse


 
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Dave - Dave.net.nz
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      10-30-2004
G'day and welcome to another Linux n00b post by me.

I'm checking the load on my machine
load average: 2.24, 2.15, 1.88
and I get that it is "now, last 5 mins, last 15 mins"

0 seems to mean idle, 1 seems to be fairly busy, 2 or over is when Im
compiling things so I assume it is ~100% CPU usage.
but what is exactly 100%? or am I barking in the wrong direction?

--
Dave Hall
http://www.dave.net.nz
http://www.karyn.net.nz
 
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thing
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Posts: n/a
 
      10-30-2004
Dave - Dave.net.nz wrote:
> G'day and welcome to another Linux n00b post by me.
>
> I'm checking the load on my machine
> load average: 2.24, 2.15, 1.88
> and I get that it is "now, last 5 mins, last 15 mins"
>
> 0 seems to mean idle, 1 seems to be fairly busy, 2 or over is when Im
> compiling things so I assume it is ~100% CPU usage.
> but what is exactly 100%? or am I barking in the wrong direction?
>


Depends on the CPU and if top is configured correctly. Load is a munge
of things, cpu, memory and disk i/o. Nominally 1 means your CPU is maxed
out, if you have 4 cpus then a load of 4 would be maxed out.

Its really more of a queue thing and not that much use for real
statistics, but a quick useful tool for a snapshot.

If your bored try this,

iostat -x 5

This will show your disk utilisation % every 5 seconds, (last column).
Ignore the first output as that is the average since your last reboot.

Once running login to another console/xterm do a find / -name <some
file> switch back and watch iostat.

vmstat can be used for a few things like cpu, but understanding what
these tools are telling you is not easy.

One really good use of top is to look for awol processes, typically if
your machine is running badly, look at the first process in top, if its
100% or 99.x% yet you would normally expect it to be 0.2% then this
suggests the process has run away. Solution is look at its PID and kill
-9 it, or -15 to be more gentle but it usually does not respond. Do be
sure you get the correct PID and are sure its simply not process working
hard for some automated reason.

regards

thing

















 
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Chris Hope
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Posts: n/a
 
      10-30-2004
Dave - Dave.net.nz wrote:

> G'day and welcome to another Linux n00b post by me.
>
> I'm checking the load on my machine
> load average: 2.24, 2.15, 1.88
> and I get that it is "now, last 5 mins, last 15 mins"
>
> 0 seems to mean idle, 1 seems to be fairly busy, 2 or over is when Im
> compiling things so I assume it is ~100% CPU usage.
> but what is exactly 100%? or am I barking in the wrong direction?


IIRC the load means the number of concurrent processes doing stuff at any
one time. You could have a load of 1 and 100% CPU usage or a load of 1 and
only 10% CPU usage depending just what that process is doing. Even with a
load of about 6 or 7 your system should still be pretty responsive.

I did a quick Google and found this page which seems to have some useful
info there about it:

http://www.teamquest.com/resources/gunther/ldavg1.shtml

--
Chris Hope - The Electric Toolbox - http://www.electrictoolbox.com/
 
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Gordon
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      10-30-2004
On Sat, 30 Oct 2004 18:19:47 +1300, thing wrote:

> One really good use of top.....[snip]


Use top, yes it is command line, but it does give you more than you need
to know.

A must have when you need/want it.

 
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Peter
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      10-30-2004
RT wrote:
> Or you can use gtop or ktop and use your mouse


ksysguard has replaced ktop (I think)


Peter

 
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Lawrence D'Oliveiro
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Posts: n/a
 
      10-30-2004
In article <dwFgd.24061$(E-Mail Removed)>,
thing <(E-Mail Removed)> wrote:

>Load is a munge of things, cpu, memory and disk i/o.


No it's not, it's just an averaged count of processes ready to use the
CPU.

>Nominally 1 means your CPU is maxed
>out, if you have 4 cpus then a load of 4 would be maxed out.


You would think so, but not true. For a single-CPU desktop system, a
load average of up to about 3 is in fact tolerable.

Depending on what they're doing, servers can go a bit higher. For
instance, one client of mine is running an in-house Web-based
application I wrote on a dedicated server, and they regularly push it to
a load average of about 6-12, which is where they seem to get optimum
throughput.

It used to be worse--it could go over 20, until I found I'd forgotten to
define a primary key for one MySQL table.
 
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Steve
Guest
Posts: n/a
 
      10-30-2004
thing wrote:
> Dave - Dave.net.nz wrote:
>
>> G'day and welcome to another Linux n00b post by me.
>>
>> I'm checking the load on my machine
>> load average: 2.24, 2.15, 1.88
>> and I get that it is "now, last 5 mins, last 15 mins"
>>
>> 0 seems to mean idle, 1 seems to be fairly busy, 2 or over is when Im
>> compiling things so I assume it is ~100% CPU usage.
>> but what is exactly 100%? or am I barking in the wrong direction?
>>

>
> Depends on the CPU and if top is configured correctly. Load is a munge
> of things, cpu, memory and disk i/o. Nominally 1 means your CPU is maxed
> out, if you have 4 cpus then a load of 4 would be maxed out.
>
> Its really more of a queue thing and not that much use for real
> statistics, but a quick useful tool for a snapshot.
>
> If your bored try this,
>
> iostat -x 5
>
> This will show your disk utilisation % every 5 seconds, (last column).
> Ignore the first output as that is the average since your last reboot.
>
> Once running login to another console/xterm do a find / -name <some
> file> switch back and watch iostat.
>
> vmstat can be used for a few things like cpu, but understanding what
> these tools are telling you is not easy.
>
> One really good use of top is to look for awol processes, typically if
> your machine is running badly, look at the first process in top, if its
> 100% or 99.x% yet you would normally expect it to be 0.2% then this
> suggests the process has run away. Solution is look at its PID and kill
> -9 it, or -15 to be more gentle but it usually does not respond. Do be
> sure you get the correct PID and are sure its simply not process working
> hard for some automated reason.
>
> regards
>
> thing
>

you mean uptime, i take it? Not top. Uptime is part of the distribution,
no matter which, top is third party software.

Load recorded is the number of processes in the run queue, plus those
waiting to run. 100% = 1 cpu running full time. 200% is 2 cpus in full
use, or (allegedly) both threads of an HT P4 running full time. There is
absolutely no 'munging' of io, memory or anything else in this figure.

Killing processes... -1 = hangup. Try that first. Personally, I'd rather
reboot than kill -9 processes as a matter of course. If processes are
running wild, find out why, dont use the M$ solution.

Steve
 
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thing
Guest
Posts: n/a
 
      10-30-2004
Steve wrote:
> thing wrote:
>
>> Dave - Dave.net.nz wrote:
>>
>>> G'day and welcome to another Linux n00b post by me.
>>>
>>> I'm checking the load on my machine
>>> load average: 2.24, 2.15, 1.88
>>> and I get that it is "now, last 5 mins, last 15 mins"
>>>
>>> 0 seems to mean idle, 1 seems to be fairly busy, 2 or over is when Im
>>> compiling things so I assume it is ~100% CPU usage.
>>> but what is exactly 100%? or am I barking in the wrong direction?
>>>

>>
>> Depends on the CPU and if top is configured correctly. Load is a munge
>> of things, cpu, memory and disk i/o. Nominally 1 means your CPU is
>> maxed out, if you have 4 cpus then a load of 4 would be maxed out.
>>
>> Its really more of a queue thing and not that much use for real
>> statistics, but a quick useful tool for a snapshot.
>>
>> If your bored try this,
>>
>> iostat -x 5
>>
>> This will show your disk utilisation % every 5 seconds, (last column).
>> Ignore the first output as that is the average since your last reboot.
>>
>> Once running login to another console/xterm do a find / -name <some
>> file> switch back and watch iostat.
>>
>> vmstat can be used for a few things like cpu, but understanding what
>> these tools are telling you is not easy.
>>
>> One really good use of top is to look for awol processes, typically if
>> your machine is running badly, look at the first process in top, if
>> its 100% or 99.x% yet you would normally expect it to be 0.2% then
>> this suggests the process has run away. Solution is look at its PID
>> and kill -9 it, or -15 to be more gentle but it usually does not
>> respond. Do be sure you get the correct PID and are sure its simply
>> not process working hard for some automated reason.
>>
>> regards
>>
>> thing
>>

> you mean uptime, i take it? Not top. Uptime is part of the distribution,
> no matter which, top is third party software.
>
> Load recorded is the number of processes in the run queue, plus those
> waiting to run. 100% = 1 cpu running full time. 200% is 2 cpus in full
> use, or (allegedly) both threads of an HT P4 running full time. There is
> absolutely no 'munging' of io, memory or anything else in this figure.
>
> Killing processes... -1 = hangup. Try that first. Personally, I'd rather
> reboot than kill -9 processes as a matter of course. If processes are
> running wild, find out why, dont use the M$ solution.
>
> Steve


I would have said that a reboot is the MS option.....from experience if
a process has gone awol, -9 is often the only thing that works, Ive
never needed a reboot from this.

regards

Thing







 
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Steve
Guest
Posts: n/a
 
      10-30-2004
thing wrote:
> Steve wrote:
>
>> thing wrote:
>>
>>> Dave - Dave.net.nz wrote:
>>>
>>>> G'day and welcome to another Linux n00b post by me.
>>>>
>>>> I'm checking the load on my machine
>>>> load average: 2.24, 2.15, 1.88
>>>> and I get that it is "now, last 5 mins, last 15 mins"
>>>>
>>>> 0 seems to mean idle, 1 seems to be fairly busy, 2 or over is when
>>>> Im compiling things so I assume it is ~100% CPU usage.
>>>> but what is exactly 100%? or am I barking in the wrong direction?
>>>>
>>>
>>> Depends on the CPU and if top is configured correctly. Load is a
>>> munge of things, cpu, memory and disk i/o. Nominally 1 means your CPU
>>> is maxed out, if you have 4 cpus then a load of 4 would be maxed out.
>>>
>>> Its really more of a queue thing and not that much use for real
>>> statistics, but a quick useful tool for a snapshot.
>>>
>>> If your bored try this,
>>>
>>> iostat -x 5
>>>
>>> This will show your disk utilisation % every 5 seconds, (last
>>> column). Ignore the first output as that is the average since your
>>> last reboot.
>>>
>>> Once running login to another console/xterm do a find / -name <some
>>> file> switch back and watch iostat.
>>>
>>> vmstat can be used for a few things like cpu, but understanding what
>>> these tools are telling you is not easy.
>>>
>>> One really good use of top is to look for awol processes, typically
>>> if your machine is running badly, look at the first process in top,
>>> if its 100% or 99.x% yet you would normally expect it to be 0.2% then
>>> this suggests the process has run away. Solution is look at its PID
>>> and kill -9 it, or -15 to be more gentle but it usually does not
>>> respond. Do be sure you get the correct PID and are sure its simply
>>> not process working hard for some automated reason.
>>>
>>> regards
>>>
>>> thing
>>>

>> you mean uptime, i take it? Not top. Uptime is part of the
>> distribution, no matter which, top is third party software.
>>
>> Load recorded is the number of processes in the run queue, plus those
>> waiting to run. 100% = 1 cpu running full time. 200% is 2 cpus in full
>> use, or (allegedly) both threads of an HT P4 running full time. There
>> is absolutely no 'munging' of io, memory or anything else in this figure.
>>
>> Killing processes... -1 = hangup. Try that first. Personally, I'd
>> rather reboot than kill -9 processes as a matter of course. If
>> processes are running wild, find out why, dont use the M$ solution.
>>
>> Steve

>
>
> I would have said that a reboot is the MS option.....from experience if
> a process has gone awol, -9 is often the only thing that works, Ive
> never needed a reboot from this.
>
> regards
>
> Thing
>


I said 'as a matter of course'. If you keep having to do it then there's
something wrong. The *nix way is to find out what, not to ignore it.

Steve
....and you kill zombies how?
 
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