[ubuntu-uk] Ubuntu unusably slow

[Gareth France]

On 07/02/13 14:18, Alan Pope wrote:
> On 07/02/13 12:47, Gareth France wrote:
>> I've just had a peek and apparently it's using swap memory right now!
>> Memory 1.5Gb of 3.5Gb used
>> Swap 658.9Mb of 3.7Gb used
>>
>
> Using swap is not a problem. Swapping is the problem.
>
> Using swap just means there's a chunk of space on disk which is set 
> aside to swap stuff into, or stuff has been swapped into it.
>
> Swapping is the act of throwing stuff out to disk or pulling stuff in. 
> Intensive swapping will slow the machine down and cause things to 
> become very sluggish.
>
> I would open a terminal (as others have suggested) and have it running 
> "vmstat 5" which will print a line every 5 seconds like this:-
>
> rocs -----------memory---------- ---swap-- -----io---- -system-- 
> ----cpu----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us 
> sy id wa
>  1  0 894156 2244868  50860 1636816    6   12   945    66   60 164 23 
>  5 72  0
>  0  0 894152 2242432  50876 1637120    6    0     6    39 1047 3910 11 
>  2 87  0
>  2  0 894148 2247616  50884 1637184    0    0     6    35  980 3671  9 
>  2 88  0
>  0  0 894148 2247588  50900 1637184    0    0     0    65  939 3379  8 
>  2 90  0
>  0  0 894148 2247260  50908 1636908    0    0     0    12  834 3111  7 
>  2 91  0
>  0  0 894148 2185816  50928 1698776    0    0     0   147 1093 4012 11 
>  2 88  0
>
>
>
> Ignore the first line, but when things go bad you'll see the numbers 
> change. The "si" and "so" columns indicate swapping, if they're 
> repeatedly non-zero then you're doing some swapping. "bi" and "bo" can 
> mean just general disk IO (like the normal stuff applications do). 
> "us" is cpu time spent running applications and "sy" is system time. 
> You may also see high "cs" (context switches) as the processor is 
> under load, flipping between one task and another, and rarely getting 
> any real work done.
>
> vmstat and top are very good for diagnosing this stuff, don't bother 
> with gui tools, they just make it worse :)
>
> Cheers,
I can see just by using system monitor that there is no current swap 
activity. I'm waiting for it's next attack so I can see what's going on. 
If nothing happens in the next day or two I'll restart thunderbird with 
the extensions and then if still nothing I'll go back to firefox. I want 
to take things one step at a time to see if I can isolate what's causing it.