Re: [gentoo-user] Re: aligning SSD partitions

[Dale <rdalek1967@gmail.com>]

Nicolas Sebrecht wrote:
> The 06/09/12, Dale wrote:
>
>> Not quite.  The theory is that if you put portages work directory on
>> tmpfs, then all the writes and such are done in ram which is faster.
> No! This is too much simplistic view to explain what you see.
>
> In practice, _all_ the writes always happen in RAM whatever backend
> storage you use.
>
> The difference you could see is if there is not enough RAM for the
> kernel cache, it will have to wait for the backend storage.
>


OK.  Step by step here so hopefully you and Neil can follow. 

Freshly booted system. 
Clear caches just to be sure

emerge foo with portages work directory on tmpfs
clear caches again
emerge foo with portages work directory on disk
clear caches again.
emerge foo with portages work directory on tmpfs
clear caches again
emerge foo with portages work directory on disk

You repeat this enough times and you see that it doesn't matter if
portage's work directory is on disk or on tmpfs.  As I said before, when
I have portage's work directory on disk, I see the drive light blinking
like crazy so it is doing something, reading or writing.  When portage's
work directory is on tmpfs, it only blinks when I first start the
process which should be unpacking the tarball and then at the end when
it is installing the package.  In between that, it is just the normal
stuff of my wallpaper changing or it checking my emails.  So, it may
store something in ram as it does in both cases but it is also storing
things on the drive or else the light would not be blinking so much. 

I'm not real big on rebooting but you and Neil are about to make me test
this and reboot between each and every test.  If nothing else, just to
show that drop_caches does the same as rebooting like kernel.org says,
except for the programs are still actually running. 

Dale

:-)  :-) 

-- 
I am only responsible for what I said ... Not for what you understood or how you interpreted my words!