How to test a syscall prior to compiling the kernel

[Andev]

On Wed, Jun 4, 2014 at 2:33 PM, Andev <debiandev at gmail.com> wrote:
> On Wed, Jun 4, 2014 at 1:56 PM,  <Valdis.Kletnieks at vt.edu> wrote:
>>
>> The trick to remember is that you probably don't want to use the ramdisk
>> as the permanent host, so...
>>
>> 1) Setup your git tree on permanent storage
>> 2) Set up your ramdisk
>> 3) cd /my/source/tree
>> 4) tar -c --exclude=.git -f - . | (cd /mnt/ramdisk && tar -xvf -)
>>
>> then cd /mnt/ramdisk and start building.  Remember if you make changes to
>> copy them back to /my/source/tree :)
>>
>> (The --exclude=.git will avoid copying about 900M onto the ramdisk.  Skip that
>> if you need the git history on the ramdisk for doing a bisect or similar)
>
> Thanks Valdis for the instructions.
>
> So I tried the following to mount a tmpfs
>
> $ sudo mount -t tmpfs -o size=2000m tmpfs ./ramlinux/
> $ tar -c --exclude=.git -f - . | (cd ~/ramlinux && tar -xvf -)
>
> And it works fine. I am not sure if tmpfs has any advantages over ramdisk.
>

So I might have jumped the bullet on saying that it works fine. I see
no difference between the compilation speed on native disk vs tmpfs.

For a defconfig this is the time I get:

real    6m35.407s
user    10m3.734s
sys    1m0.514s

I have 4 gigs RAM and as mentioned earlier I created a 2 gig tmpfs and
disabled swap. What am I missing?

$ df -Ph
tmpfs           2.0G  913M  1.1G  46% /home/andev/ramlinux

-- 
Andev