[K12OSN] LTSP slowness problem

Jim Kinney jim.kinney at gmail.com
Tue Apr 14 12:15:34 UTC 2015


That python process is eating the system.
Need cpuinfo as well. How many cores? A single core can get bogged down
swapping memory out between user jobs and system jobs.

Note: Intel cpus use their hyperthreading mode. That's only useful for
processes that are shared memory. When the use is non-shared memory work,
hyperthreading can actually slow down the system. I turn it off by default
in the bios.
On Apr 14, 2015 7:32 AM, "Kenneth Lundström" <kenneth.lundstrom at nudata.fi>
wrote:

>  Hi,
>
>
> here is a small capture of top results:
>
> top - 14:29:39 up 11 days,  5:43,  6 users,  load average: 1,98, 2,16, 2,03
> Tasks: 402 total,   3 running, 397 sleeping,   1 stopped,   1 zombie
> %Cpu(s): 12,4 us,  3,8 sy,  0,0 ni, 81,7 id,  2,0 wa,  0,0 hi,  0,1 si,
> 0,0 st
> KiB Mem:  16593728 total,  9841308 used,  6752420 free,   291936 buffers
> KiB Swap: 16773116 total,        0 used, 16773116 free.  6716260 cached Mem
>
>   PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
> 11101 xx1    20   0  110524  34928  21764 R 100,0  0,2  10231:46 python
> 18506 xx1    20   0 1000664 278496  45620 S  16,9  1,7  13:57.25 firefox
> 32129 xx2      20   0  784320 274336  44752 S   3,0  1,7  12:11.78
> thunderbird
> 32133 xx2      20   0 1058788 352892  46728 R   2,7  2,1  13:16.16 firefox
> 31698 root      20   0   10144   3268   2508 S   1,7  0,0   0:00.11 sshd
>    23 root      20   0       0      0      0 S   0,7  0,0   8:25.98
> ksoftirqd/3
> 16121 root      20   0       0      0      0 S   0,7  0,0   0:05.42
> kworker/1:2
>    18 root      20   0       0      0      0 S   0,3  0,0  10:11.20
> ksoftirqd/2
>    38 root      20   0       0      0      0 S   0,3  0,0   9:52.39
> ksoftirqd/6
>    43 root      20   0       0      0      0 S   0,3  0,0   8:30.15
> ksoftirqd/7
>  1776 xx3  20   0  335288  41872  19920 S   0,3  0,3   0:50.63
> plugin-containe
> 16798 xx4     20   0  874020 292644  45340 S   0,3  1,8   1:27.02 firefox
> 19382 xx4     20   0  233152  26560  16572 S   0,3  0,2   0:07.70
> plugin-containe
> 30002 xx2      20   0  231240  27512  17564 S   0,3  0,2   0:01.89
> plugin-containe
>
> If I remember correctly it is running on two harddisk but in mirror mode.
>
>
>
> Kenneth
>
>
>
>  -----Original message-----
> *From:* Jim Kinney <jim.kinney at gmail.com>
> *Sent:* Tuesday 14th April 2015 14:27
> *To:* Support list for open source software in schools. <k12osn at redhat.com
> >
> *Subject:* Re: [K12OSN] LTSP slowness problem
>
> Sounds like the server is just too weak for the load. RAM matters.
> Multiple hard drives can make a big difference.
> 1g network for only 7 clients is plenty unless its all youtube videos.
> On Apr 14, 2015 7:01 AM, "Kenneth Lundström" <kenneth.lundstrom at nudata.fi>
> wrote:
>
>>  Hello everyone,
>>
>>
>> I have a strange problem that I have been trying to solve for months.
>>
>>
>> A client have a setup of 6-7 LTSP terminals and one server. Because of
>> room structure we need to have 3 switches, all are 1 GB. Server has one 1GB
>> network card. As I couldn't get LTSP working on CentOS 7 I switched to
>> Ubuntu.
>>
>>
>> Problem is the slowness of the clients. If 1-2 are working everything is
>> fine, but when we have like 5 working the same time we get slowness, like
>> when writing an email in Thunderbird it just stops showing the writing on
>> the screen.
>>
>>
>> I swtich away from KDE to LightDM (I think was the name), still same.
>>
>>
>> One thing we think might be the problem is the filemanager. When somebody
>> open filemanager and looks at the folder with like 100 files everything
>> stop. All files are on the same server as LTSP is running.
>>
>>
>> Any ideas where to look for the problem and solving it.
>>
>>
>>
>> Kenneth
>>
>>
>>
>> _______________________________________________
>> K12OSN mailing list
>> K12OSN at redhat.com
>> https://www.redhat.com/mailman/listinfo/k12osn
>> For more info see <http://www.k12os.org>
>>
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