On 09/05/2012 09:03 PM, Stefan Teleman wrote:
On Wed, Sep 5, 2012 at 10:55 PM, Martin Sebor <mse...@gmail.com> wrote:
I suspect the difference is due to the overhead of the repeated
initialization and destruction of the per-object mutex in the
test. The test repeatedly creates (and discards) named locale
objects.
The per-class mutex is initialized just once in the process, no
matter how many facet objects (how many distinct named locales)
the test creates. But the per-object mutex must be created (and
destroyed) for each named locale.
Agreed.
But: if the choice is between an implementation which [1] breaks ABI
and [2] performs 20% worse -- even in contrived test cases -- than
another implementation [2] which doesn't break ABI, and performs
better than the first one, why would we even consider the first one?
Breaking the ABI is not an option (unless we rev the version).
But I'm not sure I understand what you think breaks the ABI.
We don't need to add a new mutex -- we can use the __rw_facet
member for the locking. Or did you mean something else?
Martin
--Stefan
