Gentoo Archives: gentoo-dev

From: Chris Gianelloni <wolf31o2@g.o>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] Do we want optimal performance?
Date: Wed, 08 Sep 2004 18:03:57
Message-Id: 1094667618.17323.74.camel@cgianelloni.nuvox.net
In Reply to: [gentoo-dev] Do we want optimal performance? by Klavs Klavsen
1 On Wed, 2004-09-08 at 06:15, Klavs Klavsen wrote:
2 > To me this clearly shows, that if Gentoo wants the best performance - we
3 > can't use a "one cflags fits them all" approach. I do know that if a
4 > program breaks, those CFLAGS are pulled out in the individual ebuild, but
5 > this is not due to poor performance.
6
7 Gentoo is not all about performance. While many of our users want to
8 squeeze the every drop of performance out of their systems, many use
9 Gentoo for any number of other reasons such as our philosophy, our
10 community, the manageability of portage, or even because they think
11 Larry the Cow just owns.
12
13 > IMHO the only way for Gentoo to prove its true potential - is to somehow
14 > build an array of compile options, with CPU's on X, programs on Y and
15 > GCC-version on Z. Getting the numbers for each CPU, will ofcourse require
16 > writing tests, for each program - but IMHO this can be done, if we do it
17 > one at a time.
18
19 I just want to ask where the manpower to do this will come from? We
20 would have to start over with every CPU upgrade and every toolchain
21 upgrade. It appears it would be an unending task of hours upon hours of
22 labor for each package. Have you looked at the sheer number of CFLAGS
23 available?
24
25 > I would suggest these tests be included like the gentoo-stats program, as
26 > something the individual Gentooist can choose to run after each compile -
27 > which would give him the optimal performance (and recompile X number of
28 > times to test different flags out) on his CPU/program/GCCversion
29 > combination, and at the same time, send the result to a Gentoo database.
30
31 I see no problem with it provided you could find someone to actually do
32 the work. This would be *very* boring work for most, which means it
33 would be abandoned by anyone but the most determined quite quickly.
34
35 > I know I would definetely have the patience to let it test and test again,
36 > if it meant more performance for me Smile
37
38 Excellent. Nothing is stopping you from doing exactly this on your own
39 machine, though, so go for it.
40
41 > The end result should be, that Gentoo automagically selects the optimal
42 > CFLAGS (in performance and stability - perhaps with some optimizations
43 > flagged as "unstable" so people can select "optimize for performance" vs.
44 > "optimize for stability") depending on the X, Y and Z from above.
45
46 Well, as soon as you enter in the possibility of user-defined
47 selections, then there is no point. If we're going for optimal
48 performance, we shoot for optimal performance. After all, with all this
49 test data who would know better, us, or each individual user who may or
50 may not have performed all the testing?
51
52 > I would very much like to be one of the guys that gets the ball rolling,
53 > but as I'm not a Gentoo Dev - We (or just I) need to agree with the Gentoo
54 > Dev's on how this could best be done.
55
56 You don't have to be a developer to get involved. That is one of the
57 greatest things about Gentoo.
58
59 > What do you think? am I crazy? It seems to me that the anandtech tests
60 > shows that it is more than just a 1% or 2% difference, with the right
61 > CFLAGS - and that the right CFLAGS for one program, can be the worst for
62 > another on same CPU/GCC combination.
63
64 While I agree that there can be great performance increases, I believe
65 that there is a definite trade-off between performance and
66 manageability. This would be wholly unmanageable without an army of
67 testers working around the clock until Gentoo ceased to be... *grin*
68
69 --
70 Chris Gianelloni
71 Release Engineering - Operations/QA Manager
72 Games - Developer
73 Gentoo Linux
74
75 Is your power animal a penguin?

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Re: [gentoo-dev] Do we want optimal performance? Klavs Klavsen <kl@××××.dk>