On Mon, Sep 10, 2012 at 7:13
AM, Dale
<rdalek1967@gmail.com>
wrote:
Nicolas Sebrecht wrote:
> The 07/09/12, Dale wrote:
>
>> The thing is tho, whether it is using
the memory as cache or using it
>> as
>> tmpfs, it is the same memory. There
is no difference. That's the
>> whole
>> point.
> Feel free to take your own assumptions as
undeniable truth. The way the
> kernel work with memory is the key, of
course.
>
> Now, as long as you blind yourself with
statements like that, I'm not
> going to respond anymore. I guess you
need to make some basic research.
>
I understand how the kernel uses memory. That's
why it doesn't matter
if you put portage's work directory on tmpfs or
not. I been using Linux
for a pretty good long while now. I have a pretty
good understanding of
it, especially the things that I use.
Respond or not, I know what I tested and what the
results were. They
were not just my tests and results either.
Nobody is disagreeing with your test results.
In fact, they're not even disagreeing with you
that they mean what you think they mean within the
context you're testing. They're disagreeing with
your extrapolation of your results to other
contexts. In short, all other things being equal,
your test results work out for someone in the
exact same circumstances as yourself...but there
are a _lot_ of other things that need to be equal!
Filesystem mount options can have an impact.
For example, let's say your filesystem is
configured to make writes synchronous, for general
data integrity purposes. That would slow
PORTAGE_TMP down something _fierce_.
Someone might be tweaking any number of the
knobs under 'vm' in /proc. vm.swappiness,
vm.dirty_* or vm.min_free_kbytes are ones that
caught my eye, but really most of them in there
look relevant.
Or consider that someone else might be running
drop_caches, or even sync() while your code is
running. (Heck, if there's a database, even an
sqlite database, on the same filesystem, that's
almost a guarantee.)
These may seem to be obvious, but these are the
kinds of things people were trying to get you to
be willing to acknowledge before you made blanket
assertions which covered them.