CVSROOT: /cvs
Module name: src
Changes by: bl...@cvs.openbsd.org 2025/04/16 06:51:11
Modified files:
sys/netinet : tcp_input.c
Log message:
Take socket lock in TCP input.
In preparation to run tcp_input() in parallel, the socket has to
be locked while processing incoming TCP packets. After inpcb lookup,
in addition take the socket lock and increase the socket reference
counter. The function in_pcbsolock_ref() upgrades a from a locked
inpcb to a locked socket by using mutex and refcount. syn_cache_get()
unlocks the listen socket and returns a locked socket, syn_cache_add()
relies on socket lock.
With this commit, exclusive net lock is still held. TCP thoughput
gets slower by 6% due to the additional mutex and refcount. But I
want to see if locking and refcount works, before switching tcp_input()
to shared net lock. Running TCP in parallel will more than compensate
the cost of locking.
tested as part of parallel TCP input by Mark Patruck, Hrvoje Popovski
OK mvs@
