Bristol Digest, Vol 637, Issue 6

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Today's Topics:

1. Re: What is with swap? (Keith Edmunds)
2. Re: What is with swap? (Andrew)
3. Re: Swap issue (Amias Channer)
4. Re: What is with swap? (Alex Butcher)
5. Re: What is with swap? (Amias Channer)
6. Re: What is with swap? (Andrew)
7. Re: What is with swap? (nick robinson)


----------------------------------------------------------------------

Message: 1
Date: Fri, 18 Mar 2016 08:58:24 +0000
From: Keith Edmunds <kae@midnighthax.com>
To: bristol@mailman.lug.org.uk
Cc: andrew@1dtv.com
Subject: Re: [bristol] What is with swap?
Message-ID: <20160318085824.203fd2b5@ws.midnighthax.com>
Content-Type: text/plain; charset=US-ASCII

OK, you are definitely swapping, and that is likely to be the cause of the
sluggishness.

Now run 'htop' in a terminal window (you may need to install it first).
You want to sort (F6) on the virtual memory column, but the name of that
from a sort perspective depends on the version of htop. The current Debian
version calls it "M_SIZE".

That will show you which processes are using the most virtual memory, and
the "VIRT" column will tell you how much they are using. You may well find
the same process listed multiple times. What are the top two or three
unique processes, and how much virtual memory is each using?
--
"Why does God hate me so much? Is it because I don't believe in him?" -
Sidney Morgenbesser




------------------------------

Message: 2
Date: Fri, 18 Mar 2016 09:20:58 +0000
From: Andrew <andrewsoltau@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] What is with swap?
Message-ID: <56EBC87A.1020104@1dtv.com>
Content-Type: text/plain; charset="windows-1252"; Format="flowed"

On 18/03/16 08:58, Keith Edmunds wrote:
> OK, you are definitely swapping, and that is likely to be the cause of the
> sluggishness.
>
> Now run 'htop' in a terminal window (you may need to install it first).
> You want to sort (F6) on the virtual memory column, but the name of that
> from a sort perspective depends on the version of htop. The current Debian
> version calls it "M_SIZE".
>
> That will show you which processes are using the most virtual memory, and
> the "VIRT" column will tell you how much they are using. You may well find
> the same process listed multiple times. What are the top two or three
> unique processes, and how much virtual memory is each using?

Cheers. Will do. Just restarted it to clear the problem and get on with
work but I'll do the test once it shows up again. Thanks.
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Message: 3
Date: Fri, 18 Mar 2016 09:36:16 +0000
From: Amias Channer <me@amias.net>
To: bblug@fonehelp.co.uk, Bristol and Bath Linux User Group
<bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Swap issue
Message-ID:
<CAMgU7XXt9+VEWA3ZaDW_c_UvHS420S_NS1WGBzTjoRJ4d0v01g@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

hello mike,

I believe the 4g limit was addressed by the use of PAE , most 32bit
kernels have it and some distros provide -pae kernels. It will be
slightly slower accessing ram past 4GB on 32bit using PAE than 64bit,
although your storage hardware is probably going to be a greater
bottleneck when it comes to virtualisation loads. Also newer 64bit
processors have way better virtualisation support so i'd agree thats
the best option for virtualisation.

Cheers
Amias

On 17 March 2016 at 09:37, Mike Yates <bblug@fonehelp.co.uk> wrote:
> Andrew wrote:
>> But the usage of the ram never goes over 4.something out of 7.7gb.
>
> Maybe a silly question but are you using a 64bit OS?
> (x86 = 32bit, x86-64 or AMD64 = 64bit)
>
> 32 bit OS's won't normally use over 4gb RAM and occasionally are sluggish if
> more is present. There are workarounds but 64bit systems are a no-brainer.
>
> Have fun
> Mike
>
>
> _______________________________________________
> Bristol mailing list
> Bristol@mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/bristol



------------------------------

Message: 4
Date: Fri, 18 Mar 2016 10:01:26 +0000 (GMT)
From: Alex Butcher <lug@assursys.co.uk>
To: andrew@1dtv.com, Bristol and Bath Linux User Group
<bristol@mailman.lug.org.uk>
Subject: Re: [bristol] What is with swap?
Message-ID:
<alpine.LRH.2.11.1603180959260.17724@zlgugi.of5.nffheflf.cev>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

On Thu, 17 Mar 2016, Andrew wrote:

> Home is on the ssd on a second partition with of course / on the start of
> the drive. So /tmp is on the ssd. Had not thought of putting that on the
> hdd. Could this be useful?

No - the reverse. My thinking was that some applications routinely write to
disc (whether temporary files, or in the case of browsers, their cache and
history databases). If /tmp or /home were on the HDD rather than the SSD
(with its better IO performance) that could cause performance to suffer.

Best Regards,
Alex



------------------------------

Message: 5
Date: Fri, 18 Mar 2016 10:06:58 +0000
From: Amias Channer <me@amias.net>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] What is with swap?
Message-ID:
<CAMgU7XXonnUmwdjA_4r-Nc7B+01S=30oyYkPe2EJAaOMaW1h=g@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

Hello luggers,

you can dynamically add swap space with the swapon command.

if you make a loopback on your ssd you can add and remove it to
quickly test the speed effects of using swap on ssd vs hdd.

Cheers
Amias


On 18 March 2016 at 09:20, Andrew <andrewsoltau@gmail.com> wrote:
> On 18/03/16 08:58, Keith Edmunds wrote:
>
> OK, you are definitely swapping, and that is likely to be the cause of the
> sluggishness.
>
> Now run 'htop' in a terminal window (you may need to install it first).
> You want to sort (F6) on the virtual memory column, but the name of that
> from a sort perspective depends on the version of htop. The current Debian
> version calls it "M_SIZE".
>
> That will show you which processes are using the most virtual memory, and
> the "VIRT" column will tell you how much they are using. You may well find
> the same process listed multiple times. What are the top two or three
> unique processes, and how much virtual memory is each using?
>
>
> Cheers. Will do. Just restarted it to clear the problem and get on with work
> but I'll do the test once it shows up again. Thanks.
>
> _______________________________________________
> Bristol mailing list
> Bristol@mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/bristol



------------------------------

Message: 6
Date: Fri, 18 Mar 2016 10:20:18 +0000
From: Andrew <andrewsoltau@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] What is with swap?
Message-ID: <56EBD662.5040708@1dtv.com>
Content-Type: text/plain; charset="windows-1252"; Format="flowed"

On 18/03/16 10:01, Alex Butcher wrote:
> On Thu, 17 Mar 2016, Andrew wrote:
>
>> Home is on the ssd on a second partition with of course / on the
>> start of
>> the drive. So /tmp is on the ssd. Had not thought of putting that on the
>> hdd. Could this be useful?
>
> No - the reverse. My thinking was that some applications routinely
> write to
> disc (whether temporary files, or in the case of browsers, their cache
> and
> history databases). If /tmp or /home were on the HDD rather than the SSD
> (with its better IO performance) that could cause performance to suffer.
>
> Best Regards,
> Alex
>
Oh yes, of course. Doh.
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Message: 7
Date: Fri, 18 Mar 2016 11:10:01 +0000
From: nick robinson <nick@njrobinson.net>
To: andrew@1dtv.com, Bristol and Bath Linux User Group
<bristol@mailman.lug.org.uk>
Subject: Re: [bristol] What is with swap?
Message-ID:
<CADo8qK4qw7aFiDq4Qk55bAzBS5WYM6UJeH=VyGsOm1enmn87zw@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

I would set swappiness back to 60 and then try increase cache size on
firefox.
i vaguely remember default cache size being around 50mb which would
probably cause thrashing with that many windows/tabs open

On 17 March 2016 at 18:06, Andrew <andrewsoltau@gmail.com> wrote:

> On 17/03/16 15:51, nick robinson wrote:
>
> Hi
>
> a few questions
> How many firefox windows do you have open before this becomes a problem?
> Are we talking windows or tab?
> what size is your swap?
>
>
>
> Hi
>
> Usually up to 10 windows with between 1 and 7 or 8 tabs each.
> May have another identity running - different addons - with half as many.
> swap is 11.17GiB
>
>
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