[Info-vax] Running Alpha VMS under the ES40 emulator

[Johnny Billquist]

On 2013-10-12 14:18, Simon Clubley wrote:
> On 2013-10-12, Johnny Billquist <bqt at softjar.se> wrote:
>> On 2013-10-11 16:58, George Cornelius wrote:
>>>
>>> I'm finding that what it takes to almost completely freeze
>>> up my 512 MB / 32 bit Linux system is to leave Mozilla up
>>> overnight with multiple tabs open.  It pagefaults for what
>>> seems to be a full 15 minutes at that point, and may still
>>> be nearly unusable when it all unfreezes [OK, using an
>>> external Seagate USB3 drive on a USB2 port for paging -
>>> spinning at an unspecified RPM - but you get the picture].
>>
>> Probably because you have nightly stuff run by cron which runs over the
>> disk. That causes a lot of memory to be used for disk caching, pushing
>> all applications out to swap. Which in turn cause a lot of page
>> thrashing when you try to do anything, as programs have to fight the OS
>> to get a few pages back. There is a big tendency for memory to be used
>> as disk cache nowadays...
>>
>
> No, the real problem is that Firefox has become a bloated monstrosity. :-)
> Running top or ps -axl while using Firefox can be very revealing.

That is also a problem, but it's a separate one.

It is very telling when the problem appears "after leaving the machine 
running for the night". That should tell you that something happened 
during the night...

> I've got a freshly launched firefox instance running right now with 7 tabs
> open and no other page history other than the initial Google home page.
> top is reporting that it's currently comsuming 477Mbytes of virtual
> memory, which is a insane amount of memory for a newly launched browser.

Right. But if nothing else happened, it should look the same in the morning.

> The tabs are normal HTML pages, such as Slashdot and the Register, with
> Javascript disabled and no plugins (Flash isn't even installed for this
> Firefox installation).
>
> BTW, I find 512MB to be perfectly fine for a desktop Linux machine.
> One of my systems is a old netbook with that amount of memory (it's highly
> convenient when you want to drop it in a backpack) and it does everything
> just fine. This is Scientific Linux 5.x with a Gnome 2 desktop.
>
> The only problem I have with it is when Firefox has been running for a
> period of time and I experience the same memory thrashing problems
> described above but nowhere near as bad. Other GUI applications all work
> just fine with it, BTW.
>
> You shouldn't need 1-2Gbytes to run a web browsing desktop. Unfortunately,
> there isn't any other browser around with Firefox's range of plugins.

I can easily reproduce the memory thrashing problem on most machines. I 
just need to do a find over the whole system, and observe how every 
program gets paged out while the file system cache grabs all the memory 
it can...

I don't even need a large memory´hungry program, but it becomes so much 
more obvious if I try using one of those programs...

And guess what your daily (nightly) cron jobs do...

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol