Nicolas Sebrecht wrote:
> The 05/09/12, Dale wrote:
>> Michael Mol wrote:
>>> On Wed, Sep 5, 2012 at 11:17 AM, Neil Bothwick <[email protected]> wrote:
>>>> On Wed, 05 Sep 2012 07:52:45 -0500, Dale wrote:
>>>>
>>>>>>> I might also add, I see no speed improvements in putting portages
>>>>>>> work directory on tmpfs. I have tested this a few times and the
>>>>>>> difference in compile times is just not there.
>>>>>> Probably because with 16GB everything stays cached anyway.
>>>>> I cleared the cache between the compiles. This is the command I use:
>>>>>
>>>>> echo 3 > /proc/sys/vm/drop_caches
>>>> But you are still using the RAM as disk cache during the emerge, the data
>>>> doesn't stay around long enough to need to get written to disk with so
>>>> much RAM for cache.
>>> Indeed. Try setting the mount to write-through to see the difference.
>>>
>>>
>> When I run that command, it clears all the cache. It is the same as if
>> I rebooted. Certainly you are not thinking that cache survives a reboot?
> You missed the point. One of the first thing emerge will do is to
> uncompress the package. At this time, all the files are cached in RAM.
> Hence, everything needed for the build/compilation will come from the
> cache like it would do with tmpfs.
>
You miss this point not me. I *cleared* that cache. From kernel.org:
drop_caches
Writing to this will cause the kernel to drop clean caches, dentries and
inodes from memory, causing that memory to become free.
To free pagecache:
echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:
echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes:
echo 3 > /proc/sys/vm/drop_caches
I can confirm this is done with free, top or htop. See my reply to Neil for
more on this.
Dale
:-) :-)
--
I am only responsible for what I said ... Not for what you understood or how
you interpreted my words!
