回复: [PATCH] elf: Make _dl_sort_maps prefer default DFS algorithm

Hi，

On 13/08/26 22:18, Wilco Dijkstra wrote:
> >> The default dynamic_sort tunable is 2, which maps to
> >> dso_sort_algorithm_dfs. Update the likely branch to match the
> >> default, without changing behavior for valid tunable values.
> >
> > What does this change really gain here? I am inclined to avoid this kind of
> > code churn.
>
> Is this code executed frequently or is the sorting only done once? It the latter,
> it cannot help. And if the sorting itself is expensive, it would be more useful to
> optimize that instead.
>
> So removing the __glibc_likely is best overall.

Agreed. _dl_sort_maps is only called during shared object loading/unloading, not on any hot path, so the branch predictor hint has no measurable benefit. I'll send a v2 that removes __glibc_likely and uses a plain if/else instead.

Thanks,

litenglong