Re: Route cache performance under stress

[Robert Olsson <Robert.Olsson@xxxxxxxxxxx>]

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