[Solved]which hdware is more important to save compile time?

double_crane · Last edited by double_crane on Sun Jan 20, 2013 11:06 am; edited 1 time in total

I've been gentoo desktop user for more than one year.
I'm planning to buy a better PC to substitute my present one which has been used for near 4 years.
of course install gentoo file system.

My question is
higher CPU , larger MM, or fast SSD (use as /var/portage/compile directory)
or any others factors,,
which helps more ?to save compile time..
take money into consideration too...
thank you

NeddySeagoon · Posted: Sat Jan 19, 2013 1:20 pm Post subject:

double_crane,

Its all a bit of a balancing act. With 16G RAM, you can build everything in RAM. /var/tmp/portage goes into tmpfs, so an SSD does not help with builds.
With only 4G RAM you can build most things in RAM. Firefox and LibreOffice come to mind.

CFLAGS can help speed build times. The higher your -Ox the longer the optimisation takes. -O2 is a good trade off.

CPU wise, its difficult to be exact too. Some packages will only use a single core as they break with parallel make. Most will use all the cores you have.

A SSD helps with code loading times but its a small improvement compared to CPU and RAM.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

double_crane · Posted: Sun Jan 20, 2013 8:57 am Post subject:

Thank you for you reply

as you suggest , mount memorydisk at /var/tmp/portage ,
It's a good idea . I didn't try it before.

I'm wondering if I make a ramdisk , at /var/tmp/portage ,for instance,2G size ramdisk.
when compile small software, it's OK;
but when it comes to libreoffice or firefox,the ramdisk is not large enough.
So , Will these large softwares change to compile in harddisk autoly ,
otherwise it give a error message , cancel the compile process?

Thank you.

krinn · Watchman Joined: 02 May 2003 Posts: 7470

bail out on error.

as you use your ram as harddisk, when running out of ram, you get an out of space error.
not like using harddisk for ram (swap) when you run out of ram you use your harddisk to not get out of memory.

forrestfunk81 · Guru Joined: 07 Feb 2006 Posts: 565 Location: münchen.de

You can configure which packages should be compiled using the ramdisk and which ones should be compiled using a hard disk directory. For more details take a look at this wiki page.
_________________
# cd /pub/
# more beer

NeddySeagoon · Posted: Sun Jan 20, 2013 9:39 pm Post subject:

forrestfunk81,

You can change the size of /dev/shmfs on the fly, it defaults to 50% of RAM.
Also /dev/shmfs can be swapped if you get it wrong.

There is no need to use a ramdisk for /var/tmp/portage any longer.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

forrestfunk81 · Guru Joined: 07 Feb 2006 Posts: 565 Location: münchen.de