Re: [Gnu-arch-users] Some issues

[Andrew Suffield]

On Wed, Jun 09, 2004 at 09:36:16PM +0200, Matthieu Moy wrote:
> Andrew Suffield <address@hidden> writes:
> 
> >> Do you have  a reference on this?  I've just made the test  on an ext3
> >> filesystem, and reading  10000 files of 1 lines  was incredibly faster
> >> than 1 file of 10000 lines.
> >
> > That's a fairly useless test. You're sampling buffer-cache performance
> > for sequential access, not filesystem performance for random access.
> 
> But isn't that similar  to what tla has to do to  collect file ids for
> your local tree?
> 
> To  fix the  ideas:  Suppose you  have  a project  which  is just  one
> directory  with 100  files in  it, using  explicit IDs.  tla  add will
> create 100 ID files in addition to those source files.
> 
> Now, if you  run for example "tla tree-lint", one  of the jobs carried
> out is to collect the IDs, and look for duplicates. For that, tla need
> to access  the 100 ID files,  and read one  line in each file.  With a
> 1-big-file approach,  tla would have  to read only one  100-lines long
> file,  and parse  it (There's  an overhead  due to  parsing).  This is
> simmilar to the little benchmark  I've just carried out on ext3 unless
> I've missed something.

Now you're benchmarking an operation which completes in nothing
flat. That's *completely* useless. Why on earth are you benchmarking
this? It's not a performance problem by any stretch of the
imagination.

Try to stick to one subject, and try to make it a worthwhile subject.

-- 
  .''`.  ** Debian GNU/Linux ** | Andrew Suffield
 : :' :  http://www.debian.org/ |
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