[Debian-eeepc-devel] How to deal with the freeze?

[Cristian Ionescu-Idbohrn]

On Mon, 8 Nov 2010, Ben Armstrong wrote:
> On 11/08/2010 09:41 AM, Luca Niccoli wrote:
> > On 8 November 2010 13:18, Cristian Ionescu-Idbohrn
> > <cristian.ionescu-idbohrn at axis.com> wrote:
> >>        LINUX_FULL_VER=$(uname -r)
> >>        LINUX_MINOR_MAYBE_XTRA=${LINUX_FULL_VER#*.}
> >>        LINUX_MINOR_MAYBE_XTRA=${LINUX_MINOR_MAYBE_XTRA#*.}
> >>        [ ${#LINUX_MINOR_MAYBE_XTRA} -le 5 ] || {
> >>                slak=${LINUX_MINOR_MAYBE_XTRA#?????}
> >>                LINUX_MINOR_MAYBE_XTRA=${LINUX_MINOR_MAYBE_XTRA%$slak}
> >>        }
> >
> > You're saying that you'd prefer this against:
> > LINUX_MINOR_REV=`uname -r | cut -c 5,6`
>
> The fix committed to git is fine.  I agree the alternative above is
> atrocious

But incredibly more efficient.  Dear, oh dear.  You seem to mean it :(

> (and hard to read,

Is it?  Do you mean simple and inefficient

> and if it's that complex and that necessary, should be refactored so it
> can be used elsewhere instead of copied all over the place ;)

with a smile is _the_ better way, because the tools of the trade are so
difficult to understand and learn?  Sounds like ignorance to me.  Sad :(

Let me show you some numbers [on one of my boxes: Kernel: Linux
2.6.32-5-686 (SMP w/2 CPU cores), Intel(R) Pentium(R) 4 CPU 3.40GHz].

This:

	LINUX_MINOR=$(uname -r | cut -c5,6)
	-> LINUX_MINOR='32'

repeated 10000 times uses:

	61.74s user 19.25s system 431% cpu 18.780 total

Compared to this:

	read dummy dummy LINUX_FULL_VER rest </proc/version
	LINUX_MINOR=${LINUX_FULL_VER#*.}
	LINUX_MINOR=${LINUX_MINOR#*.}
	[ ${#LINUX_MINOR} -le 2 ] || {
		chop=${LINUX_MINOR#??}
		LINUX_MINOR=${LINUX_MINOR%$chop}
	}
	-> LINUX_MINOR='32'

repeated 10000 times too, using:

	0.41s user 0.68s system 99% cpu 1.092 total

translating to the later being ~17 times more efficient than the former.

Just _one_ example, but all (hundreds, maybe thousends) the similar
inefficiencies add up to grotesk amounts :(  If this is not sufficient to
convince you, I wonder what will.


Cheers,

-- 
Cristian