Date: Thu, 08 Mar 2007 16:33:01 -0600 From: Dave Baukus <david.baukus@us.fujitsu.com> To: net@freebsd.org Subject: netisr_direct Message-ID: <45F08F1D.5080708@us.fujitsu.com> In-Reply-To: <45F03269.7050705@FreeBSD.org> References: <45C0CA5D.5090903@incunabulum.net> <45E6BEE0.2050307@FreeBSD.org> <45E6C22D.7060200@freebsd.org> <45E6D70C.10104@FreeBSD.org> <45EEB086.3050409@FreeBSD.org> <45F03269.7050705@FreeBSD.org>
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What's the word on netisr_direct ?
Do people typically enable this feature ?
net/netisr.c:
static int netisr_direct = 0;
SYSCTL_INT(_net_isr, OID_AUTO, direct, CTLFLAG_RW,
&netisr_direct, 0, "enable direct dispatch");
TUNABLE_INT("net.isr.direct", &netisr_direct);
/*
* Do direct dispatch only for MPSAFE netisrs (and
* only when enabled). Note that when a netisr is
* marked MPSAFE we permit multiple concurrent instances
* to run. We guarantee only the order in which
* packets are processed for each "dispatch point" in
* the system (i.e. call to netisr_dispatch or
* netisr_queue). This insures ordering of packets
* from an interface but does not guarantee ordering
* between multiple places in the system (e.g. IP
* dispatched from interfaces vs. IP queued from IPSec).
*/
if (netisr_direct && (ni->ni_flags & NETISR_MPSAFE)) {
isrstat.isrs_directed++;
/*
* NB: We used to drain the queue before handling
* the packet but now do not. Doing so here will
* not preserve ordering so instead we fallback to
* guaranteeing order only from dispatch points
* in the system (see above).
*/
ni->ni_handler(m);
--
Dave Baukus
david.baukus@us.fujitsu.com
972-479-2491
Fujitsu Network Communications
Richardson, Texas
USA
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