[Discuss] I need a recommendation for a Linux-compatible high-endPC builder

[Alan W. Irwin]

On 2018-01-30 20:11-0800 pw wrote:

> On 2018-01-29 06:07 PM, Alan W. Irwin wrote:
>
> Hello Alan,
>
> When you were looking at '/sys/kernel' where you looking in 'mm' at the shm 
> allocations , or in  'slab'  ?
>
> The shared memory 'shm' allocation can be problematic.
>
> I am looking around in sysfs to see if I can see what you're describing.

Hi Peter:

It turned out I got the broad outline right for that system slowdown I
kept encountering after a few days of uptime, but I didn't remember
the details right.

I have now reviewed those details from old e-mail, and the actual
problem occurred for me in 2012, and what was actually leaking were
the number of kmalloc-32 objects as reported by /proc/slabinfo/.  That
number kept rising indefinitely and at one point when I sampled it for
an e-mail to David there were almost 25 million (!) such objects
corresponding 0.8GB which was a significant fraction of the 2GB of
memory I had at that time.

Anyhow, this is very old news indeed, but nevertheless it is a
cautionary tail that leaks for any of the special memory types used by
the kernel can also be a cause of serious system slowdowns.

Alan
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Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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Linux-powered Science
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