On Tue, May 22, 2018 at 5:54 PM, Fabien Thomas <fabi...@freebsd.org> wrote:
> Author: fabient > Date: Tue May 22 15:54:25 2018 > New Revision: 334054 > URL: https://svnweb.freebsd.org/changeset/base/334054 > > Log: > Add a SPD cache to speed up lookups. > > When large SPDs are used, we face two problems: > > - too many CPU cycles are spent during the linear searches in the SPD > for each packet > - too much contention on multi socket systems, since we use a single > shared lock. > > > void > +spdcache_init(void) > +{ > + int i; > + > + TUNABLE_INT_FETCH("net.key.spdcache.maxentries", > + &V_key_spdcache_maxentries); > + TUNABLE_INT_FETCH("net.key.spdcache.threshold", > + &V_key_spdcache_threshold); > + > + if (V_key_spdcache_maxentries) { > + V_key_spdcache_maxentries = MAX(V_key_spdcache_maxentries, > + SPDCACHE_MAX_ENTRIES_PER_HASH); > + V_spdcachehashtbl = hashinit(V_key_spdcache_maxentries / > + SPDCACHE_MAX_ENTRIES_PER_HASH, > + M_IPSEC_SPDCACHE, &V_spdcachehash_mask); > + V_key_spdcache_maxentries = (V_spdcachehash_mask + 1) > + * SPDCACHE_MAX_ENTRIES_PER_HASH; > + > + V_spdcache_lock = malloc(sizeof(struct mtx) * > + (V_spdcachehash_mask + 1), > + M_IPSEC_SPDCACHE, M_WAITOK|M_ZERO); > + > + for (i = 0; i < V_spdcachehash_mask + 1; ++i) > + SPDCACHE_LOCK_INIT(i); > + } > +} > + > This ends up putting two locks per cacheline and sharing bucket heads across other lines. Unless you got a good reason not to, you should define a struct a which has both the lock and the list. An example of this can be found in kern/kern_lockf.c -- Mateusz Guzik <mjguzik gmail.com> _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
