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be represented: - A single policy namespace is defined, consisting of four possible policies: "default" to use the global default, "deferred" to force deferred dispatch, "direct" to employ direct dispatch where possible, and "hybrid" which makes a dynamic decision based on CPU affinity, ordering, etc. Routines are implemented to convert between strings and an integer namespace. - A new global variable, netisr_dispatch_policy, subsumes existing global variables for direct dispatch, forced direct dispatch, etc, and is used for explicit policy interpretation and composition. Old variables remain so that they can be exported by legacy sysctls for use by old netstat(1) binaries. A new sysctl and tunable, netisr.dispatch.policy, accepts the above strings for specifying a global policy default. - The protocol registration structure, netisr_handler, grows an nh_dispatch field, which accepts a per-policy policy override. The default value is '0', which corresponds to "default", meaning that protocols will accept the global default policy unless otherwise specified. - Policies are now interpreted and composed explicitly at various points in packet dispatch; protocol policies override global policies. - Protocols grow the ability to express a non-opinion about affinity even when implenting m2cpuid by returning NETISR_CPUID_NONE. In that case, the framework falls back on source ordering, rather than simply using the current CPU. These changes are in support of allowing link layer re-dispatch based on RSS or similar hashes provided by NICs, especially in the case where the number of hardware receive queues matches hardware core count, rather than hardware thread count, requiring further software redistributeon. (i.e., on RMI XLR). MFC after: 3 weeks Reviewed by: bz Sponsored by: Juniper Networks, Inc.
129 lines
4.7 KiB
C
129 lines
4.7 KiB
C
/*-
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* Copyright (c) 2007-2009 Robert N. M. Watson
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* Copyright (c) 2010-2011 Juniper Networks, Inc.
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* All rights reserved.
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*
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* This software was developed by Robert N. M. Watson under contract
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* to Juniper Networks, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _NET_NETISR_INTERNAL_H_
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#define _NET_NETISR_INTERNAL_H_
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#ifndef _WANT_NETISR_INTERNAL
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#error "no user-serviceable parts inside"
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#endif
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/*
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* These definitions are private to the netisr implementation, but provided
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* here for use by post-mortem crashdump analysis tools. They should not be
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* used in any other context as they can and will change. Public definitions
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* may be found in netisr.h.
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*/
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#ifndef _KERNEL
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typedef void *netisr_handler_t;
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typedef void *netisr_m2flow_t;
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typedef void *netisr_m2cpuid_t;
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typedef void *netisr_drainedcpu_t;
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#endif
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/*
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* Each protocol is described by a struct netisr_proto, which holds all
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* global per-protocol information. This data structure is set up by
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* netisr_register(), and derived from the public struct netisr_handler.
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*/
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struct netisr_proto {
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const char *np_name; /* Character string protocol name. */
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netisr_handler_t *np_handler; /* Protocol handler. */
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netisr_m2flow_t *np_m2flow; /* Query flow for untagged packet. */
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netisr_m2cpuid_t *np_m2cpuid; /* Query CPU to process packet on. */
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netisr_drainedcpu_t *np_drainedcpu; /* Callback when drained a queue. */
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u_int np_qlimit; /* Maximum per-CPU queue depth. */
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u_int np_policy; /* Work placement policy. */
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u_int np_dispatch; /* Work dispatch policy. */
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};
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#define NETISR_MAXPROT 16 /* Compile-time limit. */
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/*
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* Protocol-specific work for each workstream is described by struct
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* netisr_work. Each work descriptor consists of an mbuf queue and
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* statistics.
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*/
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struct netisr_work {
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/*
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* Packet queue, linked by m_nextpkt.
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*/
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struct mbuf *nw_head;
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struct mbuf *nw_tail;
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u_int nw_len;
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u_int nw_qlimit;
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u_int nw_watermark;
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/*
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* Statistics -- written unlocked, but mostly from curcpu.
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*/
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u_int64_t nw_dispatched; /* Number of direct dispatches. */
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u_int64_t nw_hybrid_dispatched; /* "" hybrid dispatches. */
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u_int64_t nw_qdrops; /* "" drops. */
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u_int64_t nw_queued; /* "" enqueues. */
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u_int64_t nw_handled; /* "" handled in worker. */
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};
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/*
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* Workstreams hold a queue of ordered work across each protocol, and are
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* described by netisr_workstream. Each workstream is associated with a
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* worker thread, which in turn is pinned to a CPU. Work associated with a
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* workstream can be processd in other threads during direct dispatch;
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* concurrent processing is prevented by the NWS_RUNNING flag, which
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* indicates that a thread is already processing the work queue. It is
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* important to prevent a directly dispatched packet from "skipping ahead" of
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* work already in the workstream queue.
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*/
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struct netisr_workstream {
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struct intr_event *nws_intr_event; /* Handler for stream. */
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void *nws_swi_cookie; /* swi(9) cookie for stream. */
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struct mtx nws_mtx; /* Synchronize work. */
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u_int nws_cpu; /* CPU pinning. */
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u_int nws_flags; /* Wakeup flags. */
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u_int nws_pendingbits; /* Scheduled protocols. */
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/*
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* Each protocol has per-workstream data.
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*/
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struct netisr_work nws_work[NETISR_MAXPROT];
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} __aligned(CACHE_LINE_SIZE);
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/*
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* Per-workstream flags.
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*/
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#define NWS_RUNNING 0x00000001 /* Currently running in a thread. */
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#define NWS_DISPATCHING 0x00000002 /* Currently being direct-dispatched. */
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#define NWS_SCHEDULED 0x00000004 /* Signal issued. */
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#endif /* !_NET_NETISR_INTERNAL_H_ */
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