[arch-general] Can you test machine to set --jobs[=N] from w/i PKGBUILD?

[Florian Pritz]

On 01.04.2012 13:05, Vitor Garcia wrote:
> On Sun, 1 Apr 2012 04:45:08 -0400
> Auguste Pop <auguste at gmail.com> wrote:
> 
>> anyway, i think the following command can easily get the information
>> you need: grep -c processor /proc/cpuinfo
> 
> 
> This command will make a few 2 Cores processor with some kind of
> virtual processing technology (like hyper-threading) to be counted as a
> 4 cores processor.

Which is totally fine.

> Then you just have to multiply both numbers and you know how many "real
> cpus" you have on the system. Otherwise you may be counting virtual
> processors, which shouldn't be used for heavy stuff such as compiling.

Simple tests (building readline because it's small) with -j4 and -j8 on
my i7-920 show that -j8 is around 20% faster than -j4. IIRC wikipedia
states that HT core can increase performance by up to 30%.

-- 
Florian Pritz

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