Eric Dumazet wrote:
Stephen Hemminger a écrit :
On Thu, 01 Nov 2007 11:16:20 +0100
Eric Dumazet <[EMAIL PROTECTED]> wrote:
As done two years ago on IP route cache table (commit
22c047ccbc68fa8f3fa57f0e8f906479a062c426) , we can avoid using one
lock per hash bucket for the huge TCP/DCCP hash tables.
The TCP hashes are looked at with higher frequency than the route cache yes?
On a typical x86_64 platform, this saves about 2MB or 4MB of ram, for
litle performance differences. (we hit a different cache line for the
rwlock, but then the bucket cache line have a better sharing factor
among cpus, since we dirty it less often)
Using a 'small' table of hashed rwlocks should be more than enough to
provide correct SMP concurrency between different buckets, without
using too much memory. Sizing of this table depends on NR_CPUS and
various CONFIG settings.
Something is telling me finding a 64 core system with a suitable workload to try
this could be a good thing. Wish I had one at my disposal.
rick jones
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