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diff --git a/share/man/man9/PCBGROUP.9 b/share/man/man9/PCBGROUP.9 deleted file mode 100644 index 85d1bc011f36..000000000000 --- a/share/man/man9/PCBGROUP.9 +++ /dev/null @@ -1,221 +0,0 @@ -.\" Copyright (c) 2014 Adrian Chadd -.\" 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. -.\" 3. The name of the author may not be used to endorse or promote products -.\" derived from this software without specific prior written permission. -.\" -.\" 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. -.\" -.\" $FreeBSD$ -.\" -.Dd July 23, 2014 -.Dt PCBGROUP 9 -.Os -.Sh NAME -.Nm PCBGROUP -.Nd Distributed Protocol Control Block Groups -.Sh SYNOPSIS -.Cd "options PCBGROUP" -.Pp -.In sys/param.h -.In netinet/in.h -.In netinet/in_pcb.h -.Ft void -.Fo in_pcbgroup_init -.Fa "struct inpcbinfo *pcbinfo" "u_int hashfields" "int hash_nelements" -.Fc -.Ft void -.Fn in_pcbgroup_destroy "struct inpcbinfo *pcbinfo" -.Ft struct inpcbgroup * -.Fo in_pcbgroup_byhash -.Fa "struct inpcbinfo *pcbinfo" "u_int hashtype" "uint32_t hash" -.Fc -.Ft struct inpcbgroup * -.Fn in_pcbgroup_byinpcb "struct inpcb *inp" -.Ft void -.Fn in_pcbgroup_update "struct inpcb *inp" -.Ft void -.Fn in_pcbgroup_update_mbuf "struct inpcb *inp" "struct mbuf *m" -.Ft void -.Fn in_pcbgroup_remove "struct inpcb *inp" -.Ft int -.Fn in_pcbgroup_enabled "struct inpcbinfo *pcbinfo" -.In netinet6/in6_pcb.h -.Ft struct inpcbgroup * -.Fo in6_pcbgroup_byhash -.Fa "struct inpcbinfo *pcbinfo" "u_int hashtype" "uint32_t hash" -.Fc -.Sh DESCRIPTION -This implementation introduces notions of affinity -for connections and distribute work so as to reduce lock contention, -with hardware work distribution strategies -such as RSS. -In this construction, connection groups supplement, rather than replace, -existing reservation tables for protocol 4-tuples, offering CPU-affine -lookup tables with minimal cache line migration and lock contention -during steady state operation. -.Pp -Internet protocols like 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 used as an argument to hashes that assign a connection to -a particular group. -This must be aligned with any hardware-offloaded distribution model, -such as RSS or similar approaches taken in embedded network boards. -Wildcard sockets require special handling, as in Willmann 2006, and -are shared between connection groups while being protected by -group-local locks. -Connection establishment and teardown can be signficantly more -expensive than without connection groups, but that steady-state -processing can be significantly faster. -.Pp -Enabling PCBGROUP in the kernel only provides the infrastructure -required to create and manage multiple PCB groups. -An implementation needs to fill in a few functions to provide PCB -group hash information in order for PCBs to be placed in a PCB group. -.Ss Operation -By default, each PCB info block (struct pcbinfo) has a single hash for -all PCB entries for the given protocol with a single lock protecting it. -This can be a significant source of lock contention on SMP hardware. -When a PCBGROUP is created, an array of separate hash tables are -created, each with its own lock. -A separate table for wildcard PCBs is provided. -By default, a PCBGROUP table is created for each available CPU. -The PCBGROUP code attempts to calculate a hash value from the given -PCB or mbuf when looking up a PCBGROUP. -While processing a received frame, -.Fn in_pcbgroup_byhash -can be used in conjunction with either a hardware-provided hash -value -.Po -eg the -.Xr RSS 9 -calculated hash value provided by some NICs -.Pc -or a software-provided hash value in order to choose a PCBGROUP -table to query. -A single table lock is held while performing a wildcard match. -However, all of the table locks are acquired before modifying the -wildcard table. -The PCBGROUP tables operate in conjunction with the normal single PCB list -in a PCB info block. -Thus, inserting and removing a PCB will still incur the same costs -as without PCBGROUP. -A protocol which uses PCBGROUP should fall back to the normal PCB list -lookup if a call to the PCBGROUP layer does not yield a lookup hit. -.Ss Usage -Initialize a PCBGROUP in a PCB info block -.Pq Vt "struct pcbinfo" -by calling -.Fn in_pcbgroup_init . -.Pp -Add a connection to a PCBGROUP with -.Fn in_pcbgroup_update . -Connections are removed by with -.Fn in_pcbgroup_remove . -These in turn will determine which PCBGROUP bucket the given PCB -is placed into and calculate the hash value appropriately. -.Pp -Wildcard PCBs are hashed differently and placed in a single wildcard -PCB list. -If -.Xr RSS 9 -is enabled and in use, RSS-aware wildcard PCBs are placed in a single -PCBGROUP based on RSS information. -Protocols may look up the PCB entry in a PCBGROUP by using the lookup -functions -.Fn in_pcbgroup_byhash -and -.Fn in_pcbgroup_byinpcb . -.Sh IMPLEMENTATION NOTES -The PCB code in -.Pa sys/netinet -and -.Pa sys/netinet6 -is aware of PCBGROUP and will call into the PCBGROUP code to do -PCBGROUP assignment and lookup, preferring a PCBGROUP lookup to the -default global PCB info table. -.Pp -An implementor wishing to experiment or modify the PCBGROUP assignment -should modify this set of functions: -.Bl -tag -width "12345678" -offset indent -.It Fn in_pcbgroup_getbucket No and Fn in6_pcbgroup_getbucket -Map a given 32 bit hash value to a PCBGROUP. -By default this is hash % number_of_pcbgroups. -However, this distribution may not align with NIC receive queues or -the -.Xr netisr 9 -configuration. -.It Fn in_pcbgroup_byhash No and Fn in6_pcbgroup_byhash -Map a 32 bit hash value and a hash type identifier to a PCBGROUP. -By default, this simply returns NULL. -This function is used by the -.Xr mbuf 9 -receive path in -.Pa sys/netinet/in_pcb.c -to map an mbuf to a PCBGROUP. -.It Fn in_pcbgroup_bytuple No and Fn in6_pcbgroup_bytuple -Map the source and destination address and port details to a PCBGROUP. -By default, this does a very simple XOR hash. -This function is used by both the PCB lookup code and as a fallback in -the -.Xr mbuf 9 -receive path in -.Pa sys/netinet/in_pcb.c . -.El -.Sh SEE ALSO -.Xr mbuf 9 , -.Xr netisr 9 , -.Xr RSS 9 -.Rs -.%A Paul Willmann -.%A Scott Rixner -.%A Alan L. Cox -.%T "An Evaluation of Network Stack Parallelization Strategies in Modern Operating Systems" -.%J "2006 USENIX Annual Technical Conference" -.%D 2006 -.%U http://www.ece.rice.edu/~willmann/pubs/paranet_usenix.pdf -.Re -.Sh HISTORY -PCBGROUP first appeared in -.Fx 9.0 . -.Sh AUTHORS -.An -nosplit -The PCBGROUP implementation was written by -.An Robert N. M. Watson Aq Mt rwatson@FreeBSD.org -under contract to Juniper Networks, Inc. -.Pp -This manual page written by -.An Adrian Chadd Aq Mt adrian@FreeBSD.org . -.Sh NOTES -The -.Xr RSS 9 -implementation currently uses -.Ic #ifdef -blocks to tie into PCBGROUP. -This is a sign that a more abstract programming API is needed. -.Pp -There is currently no support for re-balancing the PCBGROUP assignment, -nor is there any support for overriding which PCBGROUP a socket/PCB -should be in. -.Pp -No statistics are kept to indicate how often PCBGROUP lookups -succeed or fail. |