On Fri, Aug 25, 2006 at 09:37:46AM +0200, Ian FREISLICH wrote: > Hi > > While doing some experimentation and work on ipfw to see where I > could improve performance for our virtualised firewall I came across > the following comment in sys/net/if_vlan.c: > > * The VLAN_ARRAY substitutes the dynamic hash with a static array > * with 4096 entries. In theory this can give a boots(sic) in processing, > * however on practice it does not. Probably this is because array > * is too big to fit into CPU cache. > > Can anyone suggest a good reason not to turn this option on by > default. It looks to me like it dramatically improves performance. Its because of the amount of memory it uses, 16k doesnt sound like much but its valuable kernel memory. It was discussed a bit here, http://lists.freebsd.org/pipermail/freebsd-net/2005-October/008716.html cheers, AndrewReceived on Fri Aug 25 2006 - 06:41:29 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:38:59 UTC