Optimized kernel builds: the straight dope

[John Richard Moser]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1



Matt Zimmerman wrote:
> On Sun, Aug 20, 2006 at 03:24:12PM -0400, John Richard Moser wrote:
>> Matt Zimmerman wrote:
>>> Unlike with the kernel, it should be straightforward to benchmark real
>>> workloads as well as artificial benchmarks.  For example, a web server
>>> benchmark, system boot process, graphics benchmarks...this would require
>>> rebuilding many system components in order to construct a compelling test,
>>> but that's mostly a matter of CPU cycles.
>>>
>> Are you volunteering an i[56]86 build of all world?
> 
> I am not.  Let me know if you require further clarification.
> 
>> With something like Firefox, you are watching wall-clock time for short
>> operations and don't have the resolution to say there's any increase
>> unless you DO get something over 20% ("wow this HUGE page rendered in 24
>> seconds instead of 30").  Other things never really hit 100% CPU usage,
>> and it's hard to measure the minor fluctuations in CPU usage the
>> optimizations cause.
>>
>> If you have any ideas, I'm open to hearing them.
> 
> Set up gdm to do automatic login and stop bootchart only when the login is
> complete.  Measure time using bootchart.  That should pull in enough of the
> desktop stack to get a meaningful measurement.
> 
> This is a multi-minute process on many machines, and a gain of, say, 10%
> could be significant.  I highly doubt that compiler optimizations would
> approach this, however.
> 

Linker optimizations will; compiler optimizations may gain you a
percent.  The nice thing about hacking the linker is that it reduces
program load time; boot time involves a lot of things loading/unloading
rapidly, so reducing their load time gives obvious gains.  I've outlined
these on the Edgy+1 toolchain spec; we can discuss them later if you like.

Beyond that you have to profile each program.  Dave Jones had the right
idea, look at HAL and CUPS brain damage.


- --
All content of all messages exchanged herein are left in the
Public Domain, unless otherwise explicitly stated.

    Creative brains are a valuable, limited resource. They shouldn't be
    wasted on re-inventing the wheel when there are so many fascinating
    new problems waiting out there.
                                                 -- Eric Steven Raymond

    We will enslave their women, eat their children and rape their
    cattle!
                  -- Bosc, Evil alien overlord from the fifth dimension
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.3 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
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=adPI
-----END PGP SIGNATURE-----