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Several years after initial development, merge prototype support for

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linking NIC Receive Side Scaling (RSS) to the network stack's
connection-group implementation.  This prototype (and derived patches)
are in use at Juniper and several other FreeBSD-using companies, so
despite some reservations about its maturity, merge the patch to the
base tree so that it can be iteratively refined in collaboration rather
than maintained as a set of gradually diverging patch sets.

(1) Merge a software implementation of the Toeplitz hash specified in
    RSS implemented by David Malone.  This is used to allow suitable
    pcbgroup placement of connections before the first packet is
    received from the NIC.  Software hashing is generally avoided,
    however, due to high cost of the hash on general-purpose CPUs.

(2) In in_rss.c, maintain authoritative versions of RSS state intended
    to be pushed to each NIC, including keying material, hash
    algorithm/ configuration, and buckets.  Provide software-facing
    interfaces to hash 2- and 4-tuples for IPv4 and IPv6 using both
    the RSS standardised Toeplitz and a 'naive' variation with a hash
    efficient in software but with poor distribution properties.
    Implement rss_m2cpuid()to be used by netisr and other load
    balancing code to look up the CPU on which an mbuf should be
    processed.

(3) In the Ethernet link layer, allow netisr distribution using RSS as
    a source of policy as an alternative to source ordering; continue
    to default to direct dispatch (i.e., don't try and requeue packets
    for processing on the 'right' CPU if they arrive in a directly
    dispatchable context).

(4) Allow RSS to control tuning of connection groups in order to align
    groups with RSS buckets.  If a packet arrives on a protocol using
    connection groups, and contains a suitable hardware-generated
    hash, use that hash value to select the connection group for pcb
    lookup for both IPv4 and IPv6.  If no hardware-generated Toeplitz
    hash is available, we fall back on regular PCB lookup risking
    contention rather than pay the cost of Toeplitz in software --
    this is a less scalable but, at my last measurement, faster
    approach.  As core counts go up, we may want to revise this
    strategy despite CPU overhead.

Where device drivers suitably configure NICs, and connection groups /
RSS are enabled, this should avoid both lock and line contention during
connection lookup for TCP.  This commit does not modify any device
drivers to tune device RSS configuration to the global RSS
configuration; patches are in circulation to do this for at least
Chelsio T3 and Intel 1G/10G drivers.  Currently, the KPI for device
drivers is not particularly robust, nor aware of more advanced features
such as runtime reconfiguration/rebalancing.  This will hopefully prove
a useful starting point for refinement.

No MFC is scheduled as we will first want to nail down a more mature
and maintainable KPI/KBI for device drivers.

Sponsored by:   Juniper Networks (original work)
Sponsored by:   EMC/Isilon (patch update and merge)
This commit is contained in:
Robert Watson 2014-03-15 00:57:50 +00:00
parent 3447a66db8
commit 7527624efa
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=263198
13 changed files with 881 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/amd64/conf/GENERIC
View File

@ -28,6 +28,8 @@ options SCHED_ULE # ULE scheduler
options PREEMPTION # Enable kernel thread preemption
options INET # InterNETworking
options INET6 # IPv6 communications protocols
options PCBGROUP # Protocol control-block groups
options RSS # Receive-side scaling support
options TCP_OFFLOAD # TCP offload
options SCTP # Stream Control Transmission Protocol
options FFS # Berkeley Fast Filesystem

2
sys/conf/files
View File

@ -3267,6 +3267,7 @@ netinet/in_pcb.c optional inet | inet6
netinet/in_pcbgroup.c optional inet pcbgroup | inet6 pcbgroup
netinet/in_proto.c optional inet | inet6
netinet/in_rmx.c optional inet
netinet/in_rss.c optional inet rss | inet6 rss
netinet/ip_divert.c optional inet ipdivert ipfirewall
netinet/ip_ecn.c optional inet | inet6
netinet/ip_encap.c optional inet | inet6
@ -3308,6 +3309,7 @@ netinet/tcp_syncache.c optional inet | inet6
netinet/tcp_timer.c optional inet | inet6
netinet/tcp_timewait.c optional inet | inet6
netinet/tcp_usrreq.c optional inet | inet6
netinet/toeplitz.c optional inet rss | inet6 rss
netinet/udp_usrreq.c optional inet | inet6
netinet/libalias/alias.c optional libalias inet | netgraph_nat inet
netinet/libalias/alias_db.c optional libalias inet | netgraph_nat inet

1
sys/conf/options
View File

@ -427,6 +427,7 @@ PCBGROUP opt_pcbgroup.h
PF_DEFAULT_TO_DROP opt_pf.h
RADIX_MPATH opt_mpath.h
ROUTETABLES opt_route.h
RSS opt_rss.h
SLIP_IFF_OPTS opt_slip.h
TCPDEBUG
TCP_OFFLOAD opt_inet.h # Enable code to dispatch TCP offloading

25
sys/net/if_ethersubr.c
View File

@ -34,6 +34,7 @@
#include "opt_inet6.h"
#include "opt_netgraph.h"
#include "opt_mbuf_profiling.h"
#include "opt_rss.h"
#include <sys/param.h>
#include <sys/systm.h>
@ -70,6 +71,7 @@
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>
#include <netinet/in_rss.h>
#include <netinet/ip_carp.h>
#include <netinet/ip_var.h>
#endif
@ -583,7 +585,22 @@ ether_input_internal(struct ifnet *ifp, struct mbuf *m)
/*
* Ethernet input dispatch; by default, direct dispatch here regardless of
* global configuration.
* global configuration. However, if RSS is enabled, hook up RSS affinity
* so that when deferred or hybrid dispatch is enabled, we can redistribute
* load based on RSS.
*
* XXXRW: Would be nice if the ifnet passed up a flag indicating whether or
* not it had already done work distribution via multi-queue. Then we could
* direct dispatch in the event load balancing was already complete and
* handle the case of interfaces with different capabilities better.
*
* XXXRW: Sort of want an M_DISTRIBUTED flag to avoid multiple distributions
* at multiple layers?
*
* XXXRW: For now, enable all this only if RSS is compiled in, although it
* works fine without RSS. Need to characterise the performance overhead
* of the detour through the netisr code in the event the result is always
* direct dispatch.
*/
static void
ether_nh_input(struct mbuf *m)
@ -596,8 +613,14 @@ static struct netisr_handler ether_nh = {
.nh_name = "ether",
.nh_handler = ether_nh_input,
.nh_proto = NETISR_ETHER,
#ifdef RSS
.nh_policy = NETISR_POLICY_CPU,
.nh_dispatch = NETISR_DISPATCH_DIRECT,
.nh_m2cpuid = rss_m2cpuid,
#else
.nh_policy = NETISR_POLICY_SOURCE,
.nh_dispatch = NETISR_DISPATCH_DIRECT,
#endif
};
static void

29
sys/netinet/in_pcb.c
View File

@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_pcbgroup.h"
#include "opt_rss.h"
#include <sys/param.h>
#include <sys/systm.h>
@ -75,6 +76,7 @@ __FBSDID("$FreeBSD$");
#if defined(INET) || defined(INET6)
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_rss.h>
#include <netinet/ip_var.h>
#include <netinet/tcp_var.h>
#include <netinet/udp.h>
@ -1820,7 +1822,7 @@ struct inpcb *
in_pcblookup(struct inpcbinfo *pcbinfo, struct in_addr faddr, u_int fport,
struct in_addr laddr, u_int lport, int lookupflags, struct ifnet *ifp)
{
#if defined(PCBGROUP)
#if defined(PCBGROUP) && !defined(RSS)
struct inpcbgroup *pcbgroup;
#endif
@ -1829,7 +1831,17 @@ in_pcblookup(struct inpcbinfo *pcbinfo, struct in_addr faddr, u_int fport,
KASSERT((lookupflags & (INPLOOKUP_RLOCKPCB | INPLOOKUP_WLOCKPCB)) != 0,
("%s: LOCKPCB not set", __func__));
#if defined(PCBGROUP)
/*
* When not using RSS, use connection groups in preference to the
* reservation table when looking up 4-tuples. When using RSS, just
* use the reservation table, due to the cost of the Toeplitz hash
* in software.
*
* XXXRW: This policy belongs in the pcbgroup code, as in principle
* we could be doing RSS with a non-Toeplitz hash that is affordable
* in software.
*/
#if defined(PCBGROUP) && !defined(RSS)
if (in_pcbgroup_enabled(pcbinfo)) {
pcbgroup = in_pcbgroup_bytuple(pcbinfo, laddr, lport, faddr,
fport);
@ -1856,16 +1868,27 @@ in_pcblookup_mbuf(struct inpcbinfo *pcbinfo, struct in_addr faddr,
("%s: LOCKPCB not set", __func__));
#ifdef PCBGROUP
if (in_pcbgroup_enabled(pcbinfo)) {
/*
* If we can use a hardware-generated hash to look up the connection
* group, use that connection group to find the inpcb. Otherwise
* fall back on a software hash -- or the reservation table if we're
* using RSS.
*
* XXXRW: As above, that policy belongs in the pcbgroup code.
*/
if (in_pcbgroup_enabled(pcbinfo) &&
!(M_HASHTYPE_TEST(m, M_HASHTYPE_NONE))) {
pcbgroup = in_pcbgroup_byhash(pcbinfo, M_HASHTYPE_GET(m),
m->m_pkthdr.flowid);
if (pcbgroup != NULL)
return (in_pcblookup_group(pcbinfo, pcbgroup, faddr,
fport, laddr, lport, lookupflags, ifp));
#ifndef RSS
pcbgroup = in_pcbgroup_bytuple(pcbinfo, laddr, lport, faddr,
fport);
return (in_pcblookup_group(pcbinfo, pcbgroup, faddr, fport,
laddr, lport, lookupflags, ifp));
#endif
}
#endif
return (in_pcblookup_hash(pcbinfo, faddr, fport, laddr, lport,

77
sys/netinet/in_pcbgroup.c
View File

@ -32,6 +32,7 @@
__FBSDID("$FreeBSD$");
#include "opt_inet6.h"
#include "opt_rss.h"
#include <sys/param.h>
#include <sys/lock.h>
@ -43,6 +44,7 @@ __FBSDID("$FreeBSD$");
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_rss.h>
#ifdef INET6
#include <netinet6/in6_pcb.h>
#endif /* INET6 */
@ -60,6 +62,13 @@ __FBSDID("$FreeBSD$");
* minimal cache line migration and lock contention during steady state
* operation.
*
* Hardware-offloaded checksums are often inefficient in software -- for
* example, Toeplitz, specified by RSS, introduced a significant overhead if
* performed during per-packge processing. It is therefore desirable to fall
* back on traditional reservation table lookups without affinity where
* hardware-offloaded checksums aren't available, such as for traffic over
* non-RSS interfaces.
*
* Internet protocols, such as UDP and TCP, register to use connection groups
* by providing an ipi_hashfields value other than IPI_HASHFIELDS_NONE; this
* indicates to the connection group code whether a 2-tuple or 4-tuple is
@ -72,6 +81,11 @@ __FBSDID("$FreeBSD$");
* signficantly more expensive than without connection groups, but that
* steady-state processing can be significantly faster.
*
* When RSS is used, certain connection group parameters, such as the number
* of groups, are provided by the RSS implementation, found in in_rss.c.
* Otherwise, in_pcbgroup.c selects possible sensible parameters
* corresponding to the degree of parallelism exposed by netisr.
*
* Most of the implementation of connection groups is in this file; however,
* connection group lookup is implemented in in_pcb.c alongside reservation
* table lookups -- see in_pcblookup_group().
@ -126,11 +140,25 @@ in_pcbgroup_init(struct inpcbinfo *pcbinfo, u_int hashfields,
if (mp_ncpus == 1)
return;
#ifdef RSS
/*
* Use one group per CPU for now. If we decide to do dynamic
* rebalancing a la RSS, we'll need to shift left by at least 1.
* If we're using RSS, then RSS determines the number of connection
* groups to use: one connection group per RSS bucket. If for some
* reason RSS isn't able to provide a number of buckets, disable
* connection groups entirely.
*
* XXXRW: Can this ever happen?
*/
numpcbgroups = rss_getnumbuckets();
if (numpcbgroups == 0)
return;
#else
/*
* Otherwise, we'll just use one per CPU for now. If we decide to
* do dynamic rebalancing a la RSS, we'll need similar logic here.
*/
numpcbgroups = mp_ncpus;
#endif
pcbinfo->ipi_hashfields = hashfields;
pcbinfo->ipi_pcbgroups = malloc(numpcbgroups *
@ -146,10 +174,19 @@ in_pcbgroup_init(struct inpcbinfo *pcbinfo, u_int hashfields,
/*
* Initialise notional affinity of the pcbgroup -- for RSS,
* we want the same notion of affinity as NICs to be used.
* Just round robin for the time being.
* we want the same notion of affinity as NICs to be used. In
* the non-RSS case, just round robin for the time being.
*
* XXXRW: The notion of a bucket to CPU mapping is common at
* both pcbgroup and RSS layers -- does that mean that we
* should migrate it all from RSS to here, and just leave RSS
* responsible only for providing hashing and mapping funtions?
*/
#ifdef RSS
pcbgroup->ipg_cpu = rss_getcpu(pgn);
#else
pcbgroup->ipg_cpu = (pgn % mp_ncpus);
#endif
}
}
@ -179,23 +216,38 @@ in_pcbgroup_destroy(struct inpcbinfo *pcbinfo)
/*
* Given a hash of whatever the covered tuple might be, return a pcbgroup
* index.
* index. Where RSS is supported, try to align bucket selection with RSS CPU
* affinity strategy.
*/
static __inline u_int
in_pcbgroup_getbucket(struct inpcbinfo *pcbinfo, uint32_t hash)
{
#ifdef RSS
return (rss_getbucket(hash));
#else
return (hash % pcbinfo->ipi_npcbgroups);
#endif
}
/*
* Map a (hashtype, hash) tuple into a connection group, or NULL if the hash
* information is insufficient to identify the pcbgroup.
* information is insufficient to identify the pcbgroup. This might occur if
* a TCP packet turns up with a 2-tuple hash, or if an RSS hash is present but
* RSS is not compiled into the kernel.
*/
struct inpcbgroup *
in_pcbgroup_byhash(struct inpcbinfo *pcbinfo, u_int hashtype, uint32_t hash)
{
#ifdef RSS
if ((pcbinfo->ipi_hashfields == IPI_HASHFIELDS_4TUPLE &&
hashtype == M_HASHTYPE_RSS_TCP_IPV4) ||
(pcbinfo->ipi_hashfields == IPI_HASHFIELDS_2TUPLE &&
hashtype == M_HASHTYPE_RSS_IPV4))
return (&pcbinfo->ipi_pcbgroups[
in_pcbgroup_getbucket(pcbinfo, hash)]);
#endif
return (NULL);
}
@ -213,13 +265,26 @@ in_pcbgroup_bytuple(struct inpcbinfo *pcbinfo, struct in_addr laddr,
{
uint32_t hash;
/*
* RSS note: we pass foreign addr/port as source, and local addr/port
* as destination, as we want to align with what the hardware is
* doing.
*/
switch (pcbinfo->ipi_hashfields) {
case IPI_HASHFIELDS_4TUPLE:
#ifdef RSS
hash = rss_hash_ip4_4tuple(faddr, fport, laddr, lport);
#else
hash = faddr.s_addr ^ fport;
#endif
break;
case IPI_HASHFIELDS_2TUPLE:
#ifdef RSS
hash = rss_hash_ip4_2tuple(faddr, laddr);
#else
hash = faddr.s_addr ^ laddr.s_addr;
#endif
break;
default:

505
sys/netinet/in_rss.c Normal file
View File

@ -0,0 +1,505 @@
/*-
* Copyright (c) 2010-2011 Juniper Networks, Inc.
* All rights reserved.
*
* This software was developed by Robert N. M. Watson under contract
* to Juniper Networks, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet6.h"
#include "opt_pcbgroup.h"
#ifndef PCBGROUP
#error "options RSS depends on options PCBGROUP"
#endif
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/priv.h>
#include <sys/kernel.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_rss.h>
#include <netinet/in_var.h>
#include <netinet/toeplitz.h>
/*-
* Operating system parts of receiver-side scaling (RSS), which allows
* network cards to direct flows to particular receive queues based on hashes
* of header tuples. This implementation aligns RSS buckets with connection
* groups at the TCP/IP layer, so each bucket is associated with exactly one
* group. As a result, the group lookup structures (and lock) should have an
* effective affinity with exactly one CPU.
*
* Network device drivers needing to configure RSS will query this framework
* for parameters, such as the current RSS key, hashing policies, number of
* bits, and indirection table mapping hashes to buckets and CPUs. They may
* provide their own supplementary information, such as queue<->CPU bindings.
* It is the responsibility of the network device driver to inject packets
* into the stack on as close to the right CPU as possible, if playing by RSS
* rules.
*
* TODO:
*
* - Synchronization for rss_key and other future-configurable parameters.
* - Event handler drivers can register to pick up RSS configuration changes.
* - Should we allow rss_basecpu to be configured?
* - Randomize key on boot.
* - IPv6 support.
* - Statistics on how often there's a misalignment between hardware
* placement and pcbgroup expectations.
*/
SYSCTL_NODE(_net_inet, OID_AUTO, rss, CTLFLAG_RW, 0, "Receive-side steering");
/*
* Toeplitz is the only required hash function in the RSS spec, so use it by
* default.
*/
static u_int rss_hashalgo = RSS_HASH_TOEPLITZ;
SYSCTL_INT(_net_inet_rss, OID_AUTO, hashalgo, CTLFLAG_RD, &rss_hashalgo, 0,
"RSS hash algorithm");
TUNABLE_INT("net.inet.rss.hashalgo", &rss_hashalgo);
/*
* Size of the indirection table; at most 128 entries per the RSS spec. We
* size it to at least 2 times the number of CPUs by default to allow useful
* rebalancing. If not set explicitly with a loader tunable, we tune based
* on the number of CPUs present.
*
* XXXRW: buckets might be better to use for the tunable than bits.
*/
static u_int rss_bits;
SYSCTL_INT(_net_inet_rss, OID_AUTO, bits, CTLFLAG_RD, &rss_bits, 0,
"RSS bits");
TUNABLE_INT("net.inet.rss.bits", &rss_bits);
static u_int rss_mask;
SYSCTL_INT(_net_inet_rss, OID_AUTO, mask, CTLFLAG_RD, &rss_mask, 0,
"RSS mask");
static const u_int rss_maxbits = RSS_MAXBITS;
SYSCTL_INT(_net_inet_rss, OID_AUTO, maxbits, CTLFLAG_RD,
__DECONST(int *, &rss_maxbits), 0, "RSS maximum bits");
/*
* RSS's own count of the number of CPUs it could be using for processing.
* Bounded to 64 by RSS constants.
*/
static u_int rss_ncpus;
SYSCTL_INT(_net_inet_rss, OID_AUTO, ncpus, CTLFLAG_RD, &rss_ncpus, 0,
"Number of CPUs available to RSS");
#define RSS_MAXCPUS (1 << (RSS_MAXBITS - 1))
static const u_int rss_maxcpus = RSS_MAXCPUS;
SYSCTL_INT(_net_inet_rss, OID_AUTO, maxcpus, CTLFLAG_RD,
__DECONST(int *, &rss_maxcpus), 0, "RSS maximum CPUs that can be used");
/*
* Variable exists just for reporting rss_bits in a user-friendly way.
*/
static u_int rss_buckets;
SYSCTL_INT(_net_inet_rss, OID_AUTO, buckets, CTLFLAG_RD, &rss_buckets, 0,
"RSS buckets");
/*
* Base CPU number; devices will add this to all CPU numbers returned by the
* RSS indirection table. Currently unmodifable in FreeBSD.
*/
static const u_int rss_basecpu;
SYSCTL_INT(_net_inet_rss, OID_AUTO, basecpu, CTLFLAG_RD,
__DECONST(int *, &rss_basecpu), 0, "RSS base CPU");
/*
* RSS secret key, intended to prevent attacks on load-balancing. Its
* effectiveness may be limited by algorithm choice and available entropy
* during the boot.
*
* XXXRW: And that we don't randomize it yet!
*
* XXXRW: This default is actually the default key from Chelsio T3 cards, as
* it offers reasonable distribution, unlike all-0 keys which always
* generate a hash of 0 (upsettingly).
*/
static uint8_t rss_key[RSS_KEYSIZE] = {
0x43, 0xa3, 0x8f, 0xb0, 0x41, 0x67, 0x25, 0x3d,
0x25, 0x5b, 0x0e, 0xc2, 0x6d, 0x5a, 0x56, 0xda,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
/*
* RSS hash->CPU table, which maps hashed packet headers to particular CPUs.
* Drivers may supplement this table with a seperate CPU<->queue table when
* programming devices.
*/
struct rss_table_entry {
uint8_t rte_cpu; /* CPU affinity of bucket. */
};
static struct rss_table_entry rss_table[RSS_TABLE_MAXLEN];
static void
rss_init(__unused void *arg)
{
u_int i;
/*
* Validate tunables, coerce to sensible values.
*/
switch (rss_hashalgo) {
case RSS_HASH_TOEPLITZ:
case RSS_HASH_NAIVE:
break;
default:
printf("%s: invalid RSS hashalgo %u, coercing to %u",
__func__, rss_hashalgo, RSS_HASH_TOEPLITZ);
rss_hashalgo = RSS_HASH_TOEPLITZ;
}
/*
* Count available CPUs.
*
* XXXRW: Note incorrect assumptions regarding contiguity of this set
* elsewhere.
*/
rss_ncpus = 0;
for (i = 0; i <= mp_maxid; i++) {
if (CPU_ABSENT(i))
continue;
rss_ncpus++;
}
if (rss_ncpus > RSS_MAXCPUS)
rss_ncpus = RSS_MAXCPUS;
/*
* Tune RSS table entries to be no less than 2x the number of CPUs
* -- unless we're running uniprocessor, in which case there's not
* much point in having buckets to rearrange for load-balancing!
*/
if (rss_ncpus > 1) {
if (rss_bits == 0)
rss_bits = fls(rss_ncpus - 1) + 1;
/*
* Microsoft limits RSS table entries to 128, so apply that
* limit to both auto-detected CPU counts and user-configured
* ones.
*/
if (rss_bits == 0 || rss_bits > RSS_MAXBITS) {
printf("%s: RSS bits %u not valid, coercing to %u",
__func__, rss_bits, RSS_MAXBITS);
rss_bits = RSS_MAXBITS;
}
/*
* Figure out how many buckets to use; warn if less than the
* number of configured CPUs, although this is not a fatal
* problem.
*/
rss_buckets = (1 << rss_bits);
if (rss_buckets < rss_ncpus)
printf("%s: WARNING: rss_buckets (%u) less than "
"rss_ncpus (%u)\n", __func__, rss_buckets,
rss_ncpus);
rss_mask = rss_buckets - 1;
} else {
rss_bits = 0;
rss_buckets = 1;
rss_mask = 0;
}
/*
* Set up initial CPU assignments: round-robin by default.
*
* XXXRW: Need a mapping to non-contiguous IDs here.
*/
for (i = 0; i < rss_buckets; i++)
rss_table[i].rte_cpu = i % rss_ncpus;
/*
* Randomize rrs_key.
*
* XXXRW: Not yet. If nothing else, will require an rss_isbadkey()
* loop to check for "bad" RSS keys.
*/
}
SYSINIT(rss_init, SI_SUB_SOFTINTR, SI_ORDER_SECOND, rss_init, NULL);
static uint32_t
rss_naive_hash(u_int keylen, const uint8_t *key, u_int datalen,
const uint8_t *data)
{
uint32_t v;
u_int i;
v = 0;
for (i = 0; i < keylen; i++)
v += key[i];
for (i = 0; i < datalen; i++)
v += data[i];
return (v);
}
static uint32_t
rss_hash(u_int datalen, const uint8_t *data)
{
switch (rss_hashalgo) {
case RSS_HASH_TOEPLITZ:
return (toeplitz_hash(sizeof(rss_key), rss_key, datalen,
data));
case RSS_HASH_NAIVE:
return (rss_naive_hash(sizeof(rss_key), rss_key, datalen,
data));
default:
panic("%s: unsupported/unknown hashalgo %d", __func__,
rss_hashalgo);
}
}
/*
* Hash an IPv4 2-tuple.
*/
uint32_t
rss_hash_ip4_2tuple(struct in_addr src, struct in_addr dst)
{
uint8_t data[sizeof(src) + sizeof(dst)];
u_int datalen;
datalen = 0;
bcopy(&src, &data[datalen], sizeof(src));
datalen += sizeof(src);
bcopy(&dst, &data[datalen], sizeof(dst));
datalen += sizeof(dst);
return (rss_hash(datalen, data));
}
/*
* Hash an IPv4 4-tuple.
*/
uint32_t
rss_hash_ip4_4tuple(struct in_addr src, u_short srcport, struct in_addr dst,
u_short dstport)
{
uint8_t data[sizeof(src) + sizeof(dst) + sizeof(srcport) +
sizeof(dstport)];
u_int datalen;
datalen = 0;
bcopy(&src, &data[datalen], sizeof(src));
datalen += sizeof(src);
bcopy(&dst, &data[datalen], sizeof(dst));
datalen += sizeof(dst);
bcopy(&srcport, &data[datalen], sizeof(srcport));
datalen += sizeof(srcport);
bcopy(&dstport, &data[datalen], sizeof(dstport));
datalen += sizeof(dstport);
return (rss_hash(datalen, data));
}
#ifdef INET6
/*
* Hash an IPv6 2-tuple.
*/
uint32_t
rss_hash_ip6_2tuple(struct in6_addr src, struct in6_addr dst)
{
uint8_t data[sizeof(src) + sizeof(dst)];
u_int datalen;
datalen = 0;
bcopy(&src, &data[datalen], sizeof(src));
datalen += sizeof(src);
bcopy(&dst, &data[datalen], sizeof(dst));
datalen += sizeof(dst);
return (rss_hash(datalen, data));
}
/*
* Hash an IPv6 4-tuple.
*/
uint32_t
rss_hash_ip6_4tuple(struct in6_addr src, u_short srcport,
struct in6_addr dst, u_short dstport)
{
uint8_t data[sizeof(src) + sizeof(dst) + sizeof(srcport) +
sizeof(dstport)];
u_int datalen;
datalen = 0;
bcopy(&src, &data[datalen], sizeof(src));
datalen += sizeof(src);
bcopy(&dst, &data[datalen], sizeof(dst));
datalen += sizeof(dst);
bcopy(&srcport, &data[datalen], sizeof(srcport));
datalen += sizeof(srcport);
bcopy(&dstport, &data[datalen], sizeof(dstport));
datalen += sizeof(dstport);
return (rss_hash(datalen, data));
}
#endif /* INET6 */
/*
* Query the number of RSS bits in use.
*/
u_int
rss_getbits(void)
{
return (rss_bits);
}
/*
* Query the RSS bucket associated with an RSS hash.
*/
u_int
rss_getbucket(u_int hash)
{
return (hash & rss_mask);
}
/*
* Query the RSS CPU associated with an RSS bucket.
*/
u_int
rss_getcpu(u_int bucket)
{
return (rss_table[bucket].rte_cpu);
}
/*
* netisr CPU affinity lookup routine for use by protocols.
*/
struct mbuf *
rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid)
{
M_ASSERTPKTHDR(m);
switch (M_HASHTYPE_GET(m)) {
case M_HASHTYPE_RSS_IPV4:
case M_HASHTYPE_RSS_TCP_IPV4:
*cpuid = rss_getcpu(rss_getbucket(m->m_pkthdr.flowid));
return (m);
default:
*cpuid = NETISR_CPUID_NONE;
return (m);
}
}
/*
* Query the RSS hash algorithm.
*/
u_int
rss_gethashalgo(void)
{
return (rss_hashalgo);
}
/*
* Query the current RSS key; likely to be used by device drivers when
* configuring hardware RSS. Caller must pass an array of size RSS_KEYSIZE.
*
* XXXRW: Perhaps we should do the accept-a-length-and-truncate thing?
*/
void
rss_getkey(uint8_t *key)
{
bcopy(rss_key, key, sizeof(rss_key));
}
/*
* Query the number of buckets; this may be used by both network device
* drivers, which will need to populate hardware shadows of the software
* indirection table, and the network stack itself (such as when deciding how
* many connection groups to allocate).
*/
u_int
rss_getnumbuckets(void)
{
return (rss_buckets);
}
/*
* Query the number of CPUs in use by RSS; may be useful to device drivers
* trying to figure out how to map a larger number of CPUs into a smaller
* number of receive queues.
*/
u_int
rss_getnumcpus(void)
{
return (rss_ncpus);
}
/*
* XXXRW: Confirm that sysctl -a won't dump this keying material, don't want
* it appearing in debugging output unnecessarily.
*/
static int
sysctl_rss_key(SYSCTL_HANDLER_ARGS)
{
uint8_t temp_rss_key[RSS_KEYSIZE];
int error;
error = priv_check(req->td, PRIV_NETINET_HASHKEY);
if (error)
return (error);
bcopy(rss_key, temp_rss_key, sizeof(temp_rss_key));
error = sysctl_handle_opaque(oidp, temp_rss_key,
sizeof(temp_rss_key), req);
if (error)
return (error);
if (req->newptr != NULL) {
/* XXXRW: Not yet. */
return (EINVAL);
}
return (0);
}
SYSCTL_PROC(_net_inet_rss, OID_AUTO, key,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_rss_key,
"", "RSS keying material");

94
sys/netinet/in_rss.h Normal file
View File

@ -0,0 +1,94 @@
/*-
* Copyright (c) 2010-2011 Juniper Networks, Inc.
* All rights reserved.
*
* This software was developed by Robert N. M. Watson under contract
* to Juniper Networks, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _NETINET_IN_RSS_H_
#define _NETINET_IN_RSS_H_
#include <netinet/in.h> /* in_addr_t */
/*
* Supported RSS hash functions.
*/
#define RSS_HASH_NAIVE 0x00000001 /* Poor but fast hash. */
#define RSS_HASH_TOEPLITZ 0x00000002 /* Required by RSS. */
#define RSS_HASH_CRC32 0x00000004 /* Future; some NICs do it. */
#define RSS_HASH_MASK (RSS_HASH_NAIVE | RSS_HASH_TOEPLITZ)
/*
* Instances of struct inpcbinfo declare an RSS hash type indicating what
* header fields are covered.
*/
#define RSS_HASHFIELDS_NONE 0
#define RSS_HASHFIELDS_4TUPLE 1
#define RSS_HASHFIELDS_2TUPLE 2
/*
* Compile-time limits on the size of the indirection table.
*/
#define RSS_MAXBITS 7
#define RSS_TABLE_MAXLEN (1 << RSS_MAXBITS)
/*
* Maximum key size used throughout. It's OK for hardware to use only the
* first 16 bytes, which is all that's required for IPv4.
*/
#define RSS_KEYSIZE 40
/*
* Device driver interfaces to query RSS properties that must be programmed
* into hardware.
*/
u_int rss_getbits(void);
u_int rss_getbucket(u_int hash);
u_int rss_getcpu(u_int bucket);
void rss_getkey(uint8_t *key);
u_int rss_gethashalgo(void);
u_int rss_getnumbuckets(void);
u_int rss_getnumcpus(void);
/*
* Network stack interface to generate a hash for a protocol tuple.
*/
uint32_t rss_hash_ip4_4tuple(struct in_addr src, u_short srcport,
struct in_addr dst, u_short dstport);
uint32_t rss_hash_ip4_2tuple(struct in_addr src, struct in_addr dst);
uint32_t rss_hash_ip6_4tuple(struct in6_addr src, u_short srcport,
struct in6_addr dst, u_short dstport);
uint32_t rss_hash_ip6_2tuple(struct in6_addr src,
struct in6_addr dst);
/*
* Network stack interface to query desired CPU affinity of a packet.
*/
struct mbuf *rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid);
#endif /* !_NETINET_IN_RSS_H_ */

58
sys/netinet/toeplitz.c Normal file
View File

@ -0,0 +1,58 @@
/*-
* Copyright (c) 2010 David Malone <dwmalone@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <netinet/in_rss.h>
#include <netinet/toeplitz.h>
#include <sys/systm.h>
uint32_t
toeplitz_hash(u_int keylen, const uint8_t *key, u_int datalen,
const uint8_t *data)
{
uint32_t hash = 0, v;
u_int i, b;
/* XXXRW: Perhaps an assertion about key length vs. data length? */
v = (key[0]<<24) + (key[1]<<16) + (key[2] <<8) + key[3];
for (i = 0; i < datalen; i++) {
for (b = 0; b < 8; b++) {
if (data[i] & (1<<(7-b)))
hash ^= v;
v <<= 1;
if ((i + 4) < RSS_KEYSIZE &&
(key[i+4] & (1<<(7-b))))
v |= 1;
}
}
return (hash);
}

40
sys/netinet/toeplitz.h Normal file
View File

@ -0,0 +1,40 @@
/*-
* Copyright (c) 2010 David Malone <dwmalone@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _NETINET_TOEPLITZ_H_
#define _NETINET_TOEPLITZ_H_
/*
* Toeplitz (RSS) hash algorithm; possibly we should cache intermediate
* results between runs, in which case we'll need explicit init/destroy and
* state management.
*/
uint32_t toeplitz_hash(u_int keylen, const uint8_t *key,
u_int datalen, const uint8_t *data);
#endif /* !_NETINET_TOEPLITZ_H_ */

28
sys/netinet6/in6_pcb.c
View File

@ -71,6 +71,7 @@ __FBSDID("$FreeBSD$");
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include "opt_pcbgroup.h"
#include "opt_rss.h"
#include <sys/param.h>
#include <sys/systm.h>
@ -1136,7 +1137,7 @@ struct inpcb *
in6_pcblookup(struct inpcbinfo *pcbinfo, struct in6_addr *faddr, u_int fport,
struct in6_addr *laddr, u_int lport, int lookupflags, struct ifnet *ifp)
{
#if defined(PCBGROUP)
#if defined(PCBGROUP) && !defined(RSS)
struct inpcbgroup *pcbgroup;
#endif
@ -1145,7 +1146,17 @@ in6_pcblookup(struct inpcbinfo *pcbinfo, struct in6_addr *faddr, u_int fport,
KASSERT((lookupflags & (INPLOOKUP_RLOCKPCB | INPLOOKUP_WLOCKPCB)) != 0,
("%s: LOCKPCB not set", __func__));
#if defined(PCBGROUP)
/*
* When not using RSS, use connection groups in preference to the
* reservation table when looking up 4-tuples. When using RSS, just
* use the reservation table, due to the cost of the Toeplitz hash
* in software.
*
* XXXRW: This policy belongs in the pcbgroup code, as in principle
* we could be doing RSS with a non-Toeplitz hash that is affordable
* in software.
*/
#if defined(PCBGROUP) && !defined(RSS)
if (in_pcbgroup_enabled(pcbinfo)) {
pcbgroup = in6_pcbgroup_bytuple(pcbinfo, laddr, lport, faddr,
fport);
@ -1172,16 +1183,27 @@ in6_pcblookup_mbuf(struct inpcbinfo *pcbinfo, struct in6_addr *faddr,
("%s: LOCKPCB not set", __func__));
#ifdef PCBGROUP
if (in_pcbgroup_enabled(pcbinfo)) {
/*
* If we can use a hardware-generated hash to look up the connection
* group, use that connection group to find the inpcb. Otherwise
* fall back on a software hash -- or the reservation table if we're
* using RSS.
*
* XXXRW: As above, that policy belongs in the pcbgroup code.
*/
if (in_pcbgroup_enabled(pcbinfo) &&
!(M_HASHTYPE_TEST(m, M_HASHTYPE_NONE))) {
pcbgroup = in6_pcbgroup_byhash(pcbinfo, M_HASHTYPE_GET(m),
m->m_pkthdr.flowid);
if (pcbgroup != NULL)
return (in6_pcblookup_group(pcbinfo, pcbgroup, faddr,
fport, laddr, lport, lookupflags, ifp));
#ifndef RSS
pcbgroup = in6_pcbgroup_bytuple(pcbinfo, laddr, lport, faddr,
fport);
return (in6_pcblookup_group(pcbinfo, pcbgroup, faddr, fport,
laddr, lport, lookupflags, ifp));
#endif
}
#endif
return (in6_pcblookup_hash(pcbinfo, faddr, fport, laddr, lport,

34
sys/netinet6/in6_pcbgroup.c
View File

@ -32,35 +32,52 @@
__FBSDID("$FreeBSD$");
#include "opt_inet6.h"
#include "opt_rss.h"
#include <sys/param.h>
#include <sys/mbuf.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_rss.h>
#ifdef INET6
#include <netinet6/in6_pcb.h>
#endif /* INET6 */
/*
* Given a hash of whatever the covered tuple might be, return a pcbgroup
* index.
* index. Where RSS is supported, try to align bucket selection with RSS CPU
* affinity strategy.
*/
static __inline u_int
in6_pcbgroup_getbucket(struct inpcbinfo *pcbinfo, uint32_t hash)
{
#ifdef RSS
return (rss_getbucket(hash));
#else
return (hash % pcbinfo->ipi_npcbgroups);
#endif
}
/*
* Map a (hashtype, hash) tuple into a connection group, or NULL if the hash
* information is insufficient to identify the pcbgroup.
* information is insufficient to identify the pcbgroup. This might occur if
* a TCP packet turnsup with a 2-tuple hash, or if an RSS hash is present but
* RSS is not compiled into the kernel.
*/
struct inpcbgroup *
in6_pcbgroup_byhash(struct inpcbinfo *pcbinfo, u_int hashtype, uint32_t hash)
{
#ifdef RSS
if ((pcbinfo->ipi_hashfields == IPI_HASHFIELDS_4TUPLE &&
hashtype == M_HASHTYPE_RSS_TCP_IPV4) ||
(pcbinfo->ipi_hashfields == IPI_HASHFIELDS_2TUPLE &&
hashtype == M_HASHTYPE_RSS_IPV4))
return (&pcbinfo->ipi_pcbgroups[
in6_pcbgroup_getbucket(pcbinfo, hash)]);
#endif
return (NULL);
}
@ -78,13 +95,26 @@ in6_pcbgroup_bytuple(struct inpcbinfo *pcbinfo, const struct in6_addr *laddrp,
{
uint32_t hash;
/*
* RSS note: we pass foreign addr/port as source, and local addr/port
* as destination, as we want to align with what the hardware is
* doing.
*/
switch (pcbinfo->ipi_hashfields) {
case IPI_HASHFIELDS_4TUPLE:
#ifdef RSS
hash = rss_hash_ip6_4tuple(*faddrp, fport, *laddrp, lport);
#else
hash = faddrp->s6_addr32[3] ^ fport;
#endif
break;
case IPI_HASHFIELDS_2TUPLE:
#ifdef RSS
hash = rss_hash_ip6_2tuple(*faddrp, *laddrp);
#else
hash = faddrp->s6_addr32[3] ^ laddrp->s6_addr32[3];
#endif
break;
default:

1
sys/sys/priv.h
View File

@ -390,6 +390,7 @@
#define PRIV_NETINET_REUSEPORT 504 /* Allow [rapid] port/address reuse. */
#define PRIV_NETINET_SETHDROPTS 505 /* Set certain IPv4/6 header options. */
#define PRIV_NETINET_BINDANY 506 /* Allow bind to any address. */
#define PRIV_NETINET_HASHKEY 507 /* Get and set hash keys for IPv4/6. */
/*
* Placeholders for IPX/SPX privileges, not supported any more.