David S. Miller writes:
> But Robert, do you know "why" the dst management doesn't show up in
> your profiles when you rip-out the rtcache?
>
> It's because to total number of DST entries is so small that they all
> fit in the cpu cache. When the rtcache is enabled and we thus have up
> to "max_size" DST entries in flight at all times, the dst management
> routines show up very clearly because they have a high probability of
> missing the cpu cache.
>
> In particular, have a good look at Simon's profiles. dst_alloc() is
> quite near the top there.
Yes and that was the intention to get pretty close to pure slowpath.
As a result I/we now appreciate the hash better...
Cheers.
--ro