Automating libc comparison

Automating libc comparison

[Rich Felker]

Hi,

Here's a project I'd like to do but I thought I probably should spend
the time actually coding/maintaining, so I figured I'd post it in case
anyone else wants to help or do it:

Basic idea is to automate the libc comparison
(http://www.etalabs.net/compare_libcs.html) so that we can keep it up
to date and add new libcs (BSD? Bionic? etc.) and tests to it. A good
part of the challenge is doing tests in a fairly libc-agnostic way so
the same tests could be applied with little effort to other libcs.
Some ideas:

- Complete .a set size can be computed with -Wl,--whole-archive and
  all the standard -l options listed in POSIX.

- Complete .so set might be possible with ldd or readelf and knowledge
  of the library path.

- Most overhead/bloat measurements are easy with an appropriate test
  program and /proc.

- Resource-exhaustion tests would need test programs and could
  simulate exhaustion with resource limits.

- Performance comparisons all presently come from libc-bench, but
  there's a lot of room for replacing/improving them. It would be nice
  for some of them to be converted to units like MB/sec.

- The bottom half of the table is a lot less measurable, but at least
  some things like features might be able to be partially-automated.


Rich

Re: Automating libc comparison

[Rob Landley]

On 04/20/2013 12:46:39 PM, Rich Felker wrote:
> Hi,
> 
> Here's a project I'd like to do but I thought I probably should spend
> the time actually coding/maintaining, so I figured I'd post it in case
> anyone else wants to help or do it:
> 
> Basic idea is to automate the libc comparison
> (http://www.etalabs.net/compare_libcs.html) so that we can keep it up
> to date and add new libcs (BSD? Bionic? etc.) and tests to it. A good
> part of the challenge is doing tests in a fairly libc-agnostic way so
> the same tests could be applied with little effort to other libcs.
> Some ideas:

I note that toybox has a bsd-licensed shell script version of  
bloat-o-meter:

http://landley.net/hg/toybox/file/tip/scripts/bloatcheck

Might come in handy?

Rob