Re: Huge compile time & run time performance regression 3.3 -> HEAD

[Richard Guenther <rguenth@tat.physik.uni-tuebingen.de>]

On 19 May 2003, Gabriel Dos Reis wrote:

> Richard Guenther <rguenth@tat.physik.uni-tuebingen.de> writes:
>
> | > Do you see any compile time regressions at -O0?
> | >
> | > (I'm asking for the obvious reason: trying to find out how much work we
> | > need to do in the front end as opposed to the back end.)
> |
> | After killing all forced inlining, I get almost the same timings from 3.3
> | and 3.4, namely 42.50 and 44.89 seconds.
> |
> | Slowdown comes from
> |
> | 3.3: name lookup           :   6.92 (17%) usr   0.90 (43%) sys   7.50
> | (18%) wall
> | 3.4: name lookup           :   9.06 (22%) usr   0.81 (39%) sys  10.29
> | (23%) wall
>
> I've also noticed that name lookup time has increased from 3.3 to 3.4,
> probably mostly because now we're doing things more correctly and
> partly because we didn't really take care to optimize it.  It would be
> interesting if you could report numbers for name lookup for 3.4:
>
>   * before I applied the name lookup
>   * after I applied it (i.e. cvs as of this moment)
>
> What I've noted (and I posted figures) wkas that the patch I applied
> cut the name lookup time about half on mainline, whereas I got at
> least 20%  on branch.

If you mean

2003-05-18  Gabriel Dos Reis  <gdr@integrable-solutions.net>

        * cp-tree.h (struct lang_type_class): Replace data member tags
        with hash-table nested_udts.
        (CLASSTYPE_NESTED_UTDS): Rename from CLASSTYPE_TAGS.
        [...]

this is already included in the numbers. I.e. the 3.4 numbers are from CVS
about 2 hours ago.

Richard.