diff options
| -rw-r--r-- | Documentation/netlink/specs/netdev.yaml | 7 | ||||
| -rw-r--r-- | Documentation/networking/napi.rst | 170 | ||||
| -rw-r--r-- | fs/eventpoll.c | 36 | ||||
| -rw-r--r-- | include/linux/netdevice.h | 2 | ||||
| -rw-r--r-- | include/net/busy_poll.h | 3 | ||||
| -rw-r--r-- | include/uapi/linux/netdev.h | 1 | ||||
| -rw-r--r-- | net/core/dev.c | 39 | ||||
| -rw-r--r-- | net/core/dev.h | 25 | ||||
| -rw-r--r-- | net/core/netdev-genl-gen.c | 5 | ||||
| -rw-r--r-- | net/core/netdev-genl.c | 12 | ||||
| -rw-r--r-- | tools/include/uapi/linux/netdev.h | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/net/.gitignore | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/net/Makefile | 9 | ||||
| -rwxr-xr-x | tools/testing/selftests/net/busy_poll_test.sh | 165 | ||||
| -rw-r--r-- | tools/testing/selftests/net/busy_poller.c | 346 |
15 files changed, 816 insertions, 6 deletions
diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml index f9cb97d6106c..cbb544bd6c84 100644 --- a/Documentation/netlink/specs/netdev.yaml +++ b/Documentation/netlink/specs/netdev.yaml @@ -263,6 +263,11 @@ attribute-sets: the end of a NAPI cycle. This may add receive latency in exchange for reducing the number of frames processed by the network stack. type: uint + - + name: irq-suspend-timeout + doc: The timeout, in nanoseconds, of how long to suspend irq + processing, if event polling finds events + type: uint - name: queue attributes: @@ -653,6 +658,7 @@ operations: - pid - defer-hard-irqs - gro-flush-timeout + - irq-suspend-timeout dump: request: attributes: @@ -704,6 +710,7 @@ operations: - id - defer-hard-irqs - gro-flush-timeout + - irq-suspend-timeout kernel-family: headers: [ "linux/list.h"] diff --git a/Documentation/networking/napi.rst b/Documentation/networking/napi.rst index dfa5d549be9c..02720dd71a76 100644 --- a/Documentation/networking/napi.rst +++ b/Documentation/networking/napi.rst @@ -192,6 +192,33 @@ is reused to control the delay of the timer, while ``napi_defer_hard_irqs`` controls the number of consecutive empty polls before NAPI gives up and goes back to using hardware IRQs. +The above parameters can also be set on a per-NAPI basis using netlink via +netdev-genl. When used with netlink and configured on a per-NAPI basis, the +parameters mentioned above use hyphens instead of underscores: +``gro-flush-timeout`` and ``napi-defer-hard-irqs``. + +Per-NAPI configuration can be done programmatically in a user application +or by using a script included in the kernel source tree: +``tools/net/ynl/cli.py``. + +For example, using the script: + +.. code-block:: bash + + $ kernel-source/tools/net/ynl/cli.py \ + --spec Documentation/netlink/specs/netdev.yaml \ + --do napi-set \ + --json='{"id": 345, + "defer-hard-irqs": 111, + "gro-flush-timeout": 11111}' + +Similarly, the parameter ``irq-suspend-timeout`` can be set using netlink +via netdev-genl. There is no global sysfs parameter for this value. + +``irq-suspend-timeout`` is used to determine how long an application can +completely suspend IRQs. It is used in combination with SO_PREFER_BUSY_POLL, +which can be set on a per-epoll context basis with ``EPIOCSPARAMS`` ioctl. + .. _poll: Busy polling @@ -207,6 +234,46 @@ selected sockets or using the global ``net.core.busy_poll`` and ``net.core.busy_read`` sysctls. An io_uring API for NAPI busy polling also exists. +epoll-based busy polling +------------------------ + +It is possible to trigger packet processing directly from calls to +``epoll_wait``. In order to use this feature, a user application must ensure +all file descriptors which are added to an epoll context have the same NAPI ID. + +If the application uses a dedicated acceptor thread, the application can obtain +the NAPI ID of the incoming connection using SO_INCOMING_NAPI_ID and then +distribute that file descriptor to a worker thread. The worker thread would add +the file descriptor to its epoll context. This would ensure each worker thread +has an epoll context with FDs that have the same NAPI ID. + +Alternatively, if the application uses SO_REUSEPORT, a bpf or ebpf program can +be inserted to distribute incoming connections to threads such that each thread +is only given incoming connections with the same NAPI ID. Care must be taken to +carefully handle cases where a system may have multiple NICs. + +In order to enable busy polling, there are two choices: + +1. ``/proc/sys/net/core/busy_poll`` can be set with a time in useconds to busy + loop waiting for events. This is a system-wide setting and will cause all + epoll-based applications to busy poll when they call epoll_wait. This may + not be desirable as many applications may not have the need to busy poll. + +2. Applications using recent kernels can issue an ioctl on the epoll context + file descriptor to set (``EPIOCSPARAMS``) or get (``EPIOCGPARAMS``) ``struct + epoll_params``:, which user programs can define as follows: + +.. code-block:: c + + struct epoll_params { + uint32_t busy_poll_usecs; + uint16_t busy_poll_budget; + uint8_t prefer_busy_poll; + + /* pad the struct to a multiple of 64bits */ + uint8_t __pad; + }; + IRQ mitigation --------------- @@ -222,12 +289,111 @@ Such applications can pledge to the kernel that they will perform a busy polling operation periodically, and the driver should keep the device IRQs permanently masked. This mode is enabled by using the ``SO_PREFER_BUSY_POLL`` socket option. To avoid system misbehavior the pledge is revoked -if ``gro_flush_timeout`` passes without any busy poll call. +if ``gro_flush_timeout`` passes without any busy poll call. For epoll-based +busy polling applications, the ``prefer_busy_poll`` field of ``struct +epoll_params`` can be set to 1 and the ``EPIOCSPARAMS`` ioctl can be issued to +enable this mode. See the above section for more details. The NAPI budget for busy polling is lower than the default (which makes sense given the low latency intention of normal busy polling). This is not the case with IRQ mitigation, however, so the budget can be adjusted -with the ``SO_BUSY_POLL_BUDGET`` socket option. +with the ``SO_BUSY_POLL_BUDGET`` socket option. For epoll-based busy polling +applications, the ``busy_poll_budget`` field can be adjusted to the desired value +in ``struct epoll_params`` and set on a specific epoll context using the ``EPIOCSPARAMS`` +ioctl. See the above section for more details. + +It is important to note that choosing a large value for ``gro_flush_timeout`` +will defer IRQs to allow for better batch processing, but will induce latency +when the system is not fully loaded. Choosing a small value for +``gro_flush_timeout`` can cause interference of the user application which is +attempting to busy poll by device IRQs and softirq processing. This value +should be chosen carefully with these tradeoffs in mind. epoll-based busy +polling applications may be able to mitigate how much user processing happens +by choosing an appropriate value for ``maxevents``. + +Users may want to consider an alternate approach, IRQ suspension, to help deal +with these tradeoffs. + +IRQ suspension +-------------- + +IRQ suspension is a mechanism wherein device IRQs are masked while epoll +triggers NAPI packet processing. + +While application calls to epoll_wait successfully retrieve events, the kernel will +defer the IRQ suspension timer. If the kernel does not retrieve any events +while busy polling (for example, because network traffic levels subsided), IRQ +suspension is disabled and the IRQ mitigation strategies described above are +engaged. + +This allows users to balance CPU consumption with network processing +efficiency. + +To use this mechanism: + + 1. The per-NAPI config parameter ``irq-suspend-timeout`` should be set to the + maximum time (in nanoseconds) the application can have its IRQs + suspended. This is done using netlink, as described above. This timeout + serves as a safety mechanism to restart IRQ driver interrupt processing if + the application has stalled. This value should be chosen so that it covers + the amount of time the user application needs to process data from its + call to epoll_wait, noting that applications can control how much data + they retrieve by setting ``max_events`` when calling epoll_wait. + + 2. The sysfs parameter or per-NAPI config parameters ``gro_flush_timeout`` + and ``napi_defer_hard_irqs`` can be set to low values. They will be used + to defer IRQs after busy poll has found no data. + + 3. The ``prefer_busy_poll`` flag must be set to true. This can be done using + the ``EPIOCSPARAMS`` ioctl as described above. + + 4. The application uses epoll as described above to trigger NAPI packet + processing. + +As mentioned above, as long as subsequent calls to epoll_wait return events to +userland, the ``irq-suspend-timeout`` is deferred and IRQs are disabled. This +allows the application to process data without interference. + +Once a call to epoll_wait results in no events being found, IRQ suspension is +automatically disabled and the ``gro_flush_timeout`` and +``napi_defer_hard_irqs`` mitigation mechanisms take over. + +It is expected that ``irq-suspend-timeout`` will be set to a value much larger +than ``gro_flush_timeout`` as ``irq-suspend-timeout`` should suspend IRQs for +the duration of one userland processing cycle. + +While it is not stricly necessary to use ``napi_defer_hard_irqs`` and +``gro_flush_timeout`` to use IRQ suspension, their use is strongly +recommended. + +IRQ suspension causes the system to alternate between polling mode and +irq-driven packet delivery. During busy periods, ``irq-suspend-timeout`` +overrides ``gro_flush_timeout`` and keeps the system busy polling, but when +epoll finds no events, the setting of ``gro_flush_timeout`` and +``napi_defer_hard_irqs`` determine the next step. + +There are essentially three possible loops for network processing and +packet delivery: + +1) hardirq -> softirq -> napi poll; basic interrupt delivery +2) timer -> softirq -> napi poll; deferred irq processing +3) epoll -> busy-poll -> napi poll; busy looping + +Loop 2 can take control from Loop 1, if ``gro_flush_timeout`` and +``napi_defer_hard_irqs`` are set. + +If ``gro_flush_timeout`` and ``napi_defer_hard_irqs`` are set, Loops 2 +and 3 "wrestle" with each other for control. + +During busy periods, ``irq-suspend-timeout`` is used as timer in Loop 2, +which essentially tilts network processing in favour of Loop 3. + +If ``gro_flush_timeout`` and ``napi_defer_hard_irqs`` are not set, Loop 3 +cannot take control from Loop 1. + +Therefore, setting ``gro_flush_timeout`` and ``napi_defer_hard_irqs`` is +the recommended usage, because otherwise setting ``irq-suspend-timeout`` +might not have any discernible effect. .. _threaded: diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 1ae4542f0bd8..83bcb559b89f 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -420,7 +420,9 @@ static bool busy_loop_ep_timeout(unsigned long start_time, static bool ep_busy_loop_on(struct eventpoll *ep) { - return !!READ_ONCE(ep->busy_poll_usecs) || net_busy_loop_on(); + return !!READ_ONCE(ep->busy_poll_usecs) || + READ_ONCE(ep->prefer_busy_poll) || + net_busy_loop_on(); } static bool ep_busy_loop_end(void *p, unsigned long start_time) @@ -455,6 +457,8 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonblock) * it back in when we have moved a socket with a valid NAPI * ID onto the ready list. */ + if (prefer_busy_poll) + napi_resume_irqs(napi_id); ep->napi_id = 0; return false; } @@ -538,6 +542,22 @@ static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd, } } +static void ep_suspend_napi_irqs(struct eventpoll *ep) +{ + unsigned int napi_id = READ_ONCE(ep->napi_id); + + if (napi_id >= MIN_NAPI_ID && READ_ONCE(ep->prefer_busy_poll)) + napi_suspend_irqs(napi_id); +} + +static void ep_resume_napi_irqs(struct eventpoll *ep) +{ + unsigned int napi_id = READ_ONCE(ep->napi_id); + + if (napi_id >= MIN_NAPI_ID && READ_ONCE(ep->prefer_busy_poll)) + napi_resume_irqs(napi_id); +} + #else static inline bool ep_busy_loop(struct eventpoll *ep, int nonblock) @@ -555,6 +575,14 @@ static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd, return -EOPNOTSUPP; } +static void ep_suspend_napi_irqs(struct eventpoll *ep) +{ +} + +static void ep_resume_napi_irqs(struct eventpoll *ep) +{ +} + #endif /* CONFIG_NET_RX_BUSY_POLL */ /* @@ -786,6 +814,7 @@ static bool ep_refcount_dec_and_test(struct eventpoll *ep) static void ep_free(struct eventpoll *ep) { + ep_resume_napi_irqs(ep); mutex_destroy(&ep->mtx); free_uid(ep->user); wakeup_source_unregister(ep->ws); @@ -2003,8 +2032,11 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, * trying again in search of more luck. */ res = ep_send_events(ep, events, maxevents); - if (res) + if (res) { + if (res > 0) + ep_suspend_napi_irqs(ep); return res; + } } if (timed_out) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index df4483598628..0aae346d919e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -348,6 +348,7 @@ struct gro_list { */ struct napi_config { u64 gro_flush_timeout; + u64 irq_suspend_timeout; u32 defer_hard_irqs; unsigned int napi_id; }; @@ -384,6 +385,7 @@ struct napi_struct { struct hrtimer timer; struct task_struct *thread; unsigned long gro_flush_timeout; + unsigned long irq_suspend_timeout; u32 defer_hard_irqs; /* control-path-only fields follow */ struct list_head dev_list; diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h index f03040baaefd..c858270141bc 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -52,6 +52,9 @@ void napi_busy_loop_rcu(unsigned int napi_id, bool (*loop_end)(void *, unsigned long), void *loop_end_arg, bool prefer_busy_poll, u16 budget); +void napi_suspend_irqs(unsigned int napi_id); +void napi_resume_irqs(unsigned int napi_id); + #else /* CONFIG_NET_RX_BUSY_POLL */ static inline unsigned long net_busy_loop_on(void) { diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h index e3ebb49f60d2..e4be227d3ad6 100644 --- a/include/uapi/linux/netdev.h +++ b/include/uapi/linux/netdev.h @@ -124,6 +124,7 @@ enum { NETDEV_A_NAPI_PID, NETDEV_A_NAPI_DEFER_HARD_IRQS, NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT, + NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT, __NETDEV_A_NAPI_MAX, NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1) diff --git a/net/core/dev.c b/net/core/dev.c index 6a31152e4606..13d00fc10f55 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6507,6 +6507,43 @@ void napi_busy_loop(unsigned int napi_id, } EXPORT_SYMBOL(napi_busy_loop); +void napi_suspend_irqs(unsigned int napi_id) +{ + struct napi_struct *napi; + + rcu_read_lock(); + napi = napi_by_id(napi_id); + if (napi) { + unsigned long timeout = napi_get_irq_suspend_timeout(napi); + + if (timeout) + hrtimer_start(&napi->timer, ns_to_ktime(timeout), + HRTIMER_MODE_REL_PINNED); + } + rcu_read_unlock(); +} + +void napi_resume_irqs(unsigned int napi_id) +{ + struct napi_struct *napi; + + rcu_read_lock(); + napi = napi_by_id(napi_id); + if (napi) { + /* If irq_suspend_timeout is set to 0 between the call to + * napi_suspend_irqs and now, the original value still + * determines the safety timeout as intended and napi_watchdog + * will resume irq processing. + */ + if (napi_get_irq_suspend_timeout(napi)) { + local_bh_disable(); + napi_schedule(napi); + local_bh_enable(); + } + } + rcu_read_unlock(); +} + #endif /* CONFIG_NET_RX_BUSY_POLL */ static void __napi_hash_add_with_id(struct napi_struct *napi, @@ -6666,6 +6703,7 @@ static void napi_restore_config(struct napi_struct *n) { n->defer_hard_irqs = n->config->defer_hard_irqs; n->gro_flush_timeout = n->config->gro_flush_timeout; + n->irq_suspend_timeout = n->config->irq_suspend_timeout; /* a NAPI ID might be stored in the config, if so use it. if not, use * napi_hash_add to generate one for us. It will be saved to the config * in napi_disable. @@ -6680,6 +6718,7 @@ static void napi_save_config(struct napi_struct *n) { n->config->defer_hard_irqs = n->defer_hard_irqs; n->config->gro_flush_timeout = n->gro_flush_timeout; + n->config->irq_suspend_timeout = n->irq_suspend_timeout; n->config->napi_id = n->napi_id; napi_hash_del(n); } diff --git a/net/core/dev.h b/net/core/dev.h index 7881bced70a9..d043dee25a68 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -236,6 +236,31 @@ static inline void netdev_set_gro_flush_timeout(struct net_device *netdev, netdev->napi_config[i].gro_flush_timeout = timeout; } +/** + * napi_get_irq_suspend_timeout - get the irq_suspend_timeout + * @n: napi struct to get the irq_suspend_timeout from + * + * Return: the per-NAPI value of the irq_suspend_timeout field. + */ +static inline unsigned long +napi_get_irq_suspend_timeout(const struct napi_struct *n) +{ + return READ_ONCE(n->irq_suspend_timeout); +} + +/** + * napi_set_irq_suspend_timeout - set the irq_suspend_timeout for a napi + * @n: napi struct to set the irq_suspend_timeout + * @timeout: timeout value to set + * + * napi_set_irq_suspend_timeout sets the per-NAPI irq_suspend_timeout + */ +static inline void napi_set_irq_suspend_timeout(struct napi_struct *n, + unsigned long timeout) +{ + WRITE_ONCE(n->irq_suspend_timeout, timeout); +} + int rps_cpumask_housekeeping(struct cpumask *mask); #if defined(CONFIG_DEBUG_NET) && defined(CONFIG_BPF_SYSCALL) diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c index 21de7e10be16..a89cbd8d87c3 100644 --- a/net/core/netdev-genl-gen.c +++ b/net/core/netdev-genl-gen.c @@ -92,10 +92,11 @@ static const struct nla_policy netdev_bind_rx_nl_policy[NETDEV_A_DMABUF_FD + 1] }; /* NETDEV_CMD_NAPI_SET - do */ -static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT + 1] = { +static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT + 1] = { [NETDEV_A_NAPI_ID] = { .type = NLA_U32, }, [NETDEV_A_NAPI_DEFER_HARD_IRQS] = NLA_POLICY_FULL_RANGE(NLA_U32, &netdev_a_napi_defer_hard_irqs_range), [NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT] = { .type = NLA_UINT, }, + [NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT] = { .type = NLA_UINT, }, }; /* Ops table for netdev */ @@ -186,7 +187,7 @@ static const struct genl_split_ops netdev_nl_ops[] = { .cmd = NETDEV_CMD_NAPI_SET, .doit = netdev_nl_napi_set_doit, .policy = netdev_napi_set_nl_policy, - .maxattr = NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT, + .maxattr = NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT, .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO, }, }; diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c index b49c3b4e5fbe..765ce7c9d73b 100644 --- a/net/core/netdev-genl.c +++ b/net/core/netdev-genl.c @@ -161,6 +161,7 @@ static int netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi, const struct genl_info *info) { + unsigned long irq_suspend_timeout; unsigned long gro_flush_timeout; u32 napi_defer_hard_irqs; void *hdr; @@ -196,6 +197,11 @@ netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi, napi_defer_hard_irqs)) goto nla_put_failure; + irq_suspend_timeout = napi_get_irq_suspend_timeout(napi); + if (nla_put_uint(rsp, NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT, + irq_suspend_timeout)) + goto nla_put_failure; + gro_flush_timeout = napi_get_gro_flush_timeout(napi); if (nla_put_uint(rsp, NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT, gro_flush_timeout)) @@ -306,6 +312,7 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb) static int netdev_nl_napi_set_config(struct napi_struct *napi, struct genl_info *info) { + u64 irq_suspend_timeout = 0; u64 gro_flush_timeout = 0; u32 defer = 0; @@ -314,6 +321,11 @@ netdev_nl_napi_set_config(struct napi_struct *napi, struct genl_info *info) napi_set_defer_hard_irqs(napi, defer); } + if (info->attrs[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT]) { + irq_suspend_timeout = nla_get_uint(info->attrs[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT]); + napi_set_irq_suspend_timeout(napi, irq_suspend_timeout); + } + if (info->attrs[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT]) { gro_flush_timeout = nla_get_uint(info->attrs[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT]); napi_set_gro_flush_timeout(napi, gro_flush_timeout); diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h index e3ebb49f60d2..e4be227d3ad6 100644 --- a/tools/include/uapi/linux/netdev.h +++ b/tools/include/uapi/linux/netdev.h @@ -124,6 +124,7 @@ enum { NETDEV_A_NAPI_PID, NETDEV_A_NAPI_DEFER_HARD_IRQS, NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT, + NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT, __NETDEV_A_NAPI_MAX, NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1) diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore index a78debbd1fe7..48973e78d46b 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -2,6 +2,7 @@ bind_bhash bind_timewait bind_wildcard +busy_poller cmsg_sender diag_uid epoll_busy_poll diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 9322b904ad00..2b2a5ec7fa6a 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -97,6 +97,11 @@ TEST_PROGS += fq_band_pktlimit.sh TEST_PROGS += vlan_hw_filter.sh TEST_PROGS += bpf_offload.py TEST_PROGS += ipv6_route_update_soft_lockup.sh +TEST_PROGS += busy_poll_test.sh + +# YNL files, must be before "include ..lib.mk" +YNL_GEN_FILES := busy_poller +TEST_GEN_FILES += $(YNL_GEN_FILES) TEST_FILES := settings TEST_FILES += in_netns.sh lib.sh net_helper.sh setup_loopback.sh setup_veth.sh @@ -107,6 +112,10 @@ TEST_INCLUDES := forwarding/lib.sh include ../lib.mk +# YNL build +YNL_GENS := netdev +include ynl.mk + $(OUTPUT)/epoll_busy_poll: LDLIBS += -lcap $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread -lcrypto diff --git a/tools/testing/selftests/net/busy_poll_test.sh b/tools/testing/selftests/net/busy_poll_test.sh new file mode 100755 index 000000000000..7db292ec4884 --- /dev/null +++ b/tools/testing/selftests/net/busy_poll_test.sh @@ -0,0 +1,165 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +source net_helper.sh + +NSIM_SV_ID=$((256 + RANDOM % 256)) +NSIM_SV_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_SV_ID +NSIM_CL_ID=$((512 + RANDOM % 256)) +NSIM_CL_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_CL_ID + +NSIM_DEV_SYS_NEW=/sys/bus/netdevsim/new_device +NSIM_DEV_SYS_DEL=/sys/bus/netdevsim/del_device +NSIM_DEV_SYS_LINK=/sys/bus/netdevsim/link_device +NSIM_DEV_SYS_UNLINK=/sys/bus/netdevsim/unlink_device + +SERVER_IP=192.168.1.1 +CLIENT_IP=192.168.1.2 +SERVER_PORT=48675 + +# busy poll config +MAX_EVENTS=8 +BUSY_POLL_USECS=0 +BUSY_POLL_BUDGET=16 +PREFER_BUSY_POLL=1 + +# IRQ deferral config +NAPI_DEFER_HARD_IRQS=100 +GRO_FLUSH_TIMEOUT=50000 +SUSPEND_TIMEOUT=20000000 + +setup_ns() +{ + set -e + ip netns add nssv + ip netns add nscl + + NSIM_SV_NAME=$(find $NSIM_SV_SYS/net -maxdepth 1 -type d ! \ + -path $NSIM_SV_SYS/net -exec basename {} \;) + NSIM_CL_NAME=$(find $NSIM_CL_SYS/net -maxdepth 1 -type d ! \ + -path $NSIM_CL_SYS/net -exec basename {} \;) + + # ensure the server has 1 queue + ethtool -L $NSIM_SV_NAME combined 1 2>/dev/null + + ip link set $NSIM_SV_NAME netns nssv + ip link set $NSIM_CL_NAME netns nscl + + ip netns exec nssv ip addr add "${SERVER_IP}/24" dev $NSIM_SV_NAME + ip netns exec nscl ip addr add "${CLIENT_IP}/24" dev $NSIM_CL_NAME + + ip netns exec nssv ip link set dev $NSIM_SV_NAME up + ip netns exec nscl ip link set dev $NSIM_CL_NAME up + + set +e +} + +cleanup_ns() +{ + ip netns del nscl + ip netns del nssv +} + +test_busypoll() +{ + suspend_value=${1:-0} + tmp_file=$(mktemp) + out_file=$(mktemp) + + # fill a test file with random data + dd if=/dev/urandom of=${tmp_file} bs=1M count=1 2> /dev/null + + timeout -k 1s 30s ip netns exec nssv ./busy_poller \ + -p${SERVER_PORT} \ + -b${SERVER_IP} \ + -m${MAX_EVENTS} \ + -u${BUSY_POLL_USECS} \ + -P${PREFER_BUSY_POLL} \ + -g${BUSY_POLL_BUDGET} \ + -i${NSIM_SV_IFIDX} \ + -s${suspend_value} \ + -o${out_file}& + + wait_local_port_listen nssv ${SERVER_PORT} tcp + + ip netns exec nscl socat -u $tmp_file TCP:${SERVER_IP}:${SERVER_PORT} + + wait + + tmp_file_md5sum=$(md5sum $tmp_file | cut -f1 -d' ') + out_file_md5sum=$(md5sum $out_file | cut -f1 -d' ') + + if [ "$tmp_file_md5sum" = "$out_file_md5sum" ]; then + res=0 + else + echo "md5sum mismatch" + echo "input file md5sum: ${tmp_file_md5sum}"; + echo "output file md5sum: ${out_file_md5sum}"; + res=1 + fi + + rm $out_file $tmp_file + + return $res +} + +test_busypoll_with_suspend() +{ + test_busypoll ${SUSPEND_TIMEOUT} + + return $? +} + +### +### Code start +### + +modprobe netdevsim + +# linking + +echo $NSIM_SV_ID > $NSIM_DEV_SYS_NEW +echo $NSIM_CL_ID > $NSIM_DEV_SYS_NEW +udevadm settle + +setup_ns + +NSIM_SV_FD=$((256 + RANDOM % 256)) +exec {NSIM_SV_FD}</var/run/netns/nssv +NSIM_SV_IFIDX=$(ip netns exec nssv cat /sys/class/net/$NSIM_SV_NAME/ifindex) + +NSIM_CL_FD=$((256 + RANDOM % 256)) +exec {NSIM_CL_FD}</var/run/netns/nscl +NSIM_CL_IFIDX=$(ip netns exec nscl cat /sys/class/net/$NSIM_CL_NAME/ifindex) + +echo "$NSIM_SV_FD:$NSIM_SV_IFIDX $NSIM_CL_FD:$NSIM_CL_IFIDX" > \ + $NSIM_DEV_SYS_LINK + +if [ $? -ne 0 ]; then + echo "linking netdevsim1 with netdevsim2 should succeed" + cleanup_ns + exit 1 +fi + +test_busypoll +if [ $? -ne 0 ]; then + echo "test_busypoll failed" + cleanup_ns + exit 1 +fi + +test_busypoll_with_suspend +if [ $? -ne 0 ]; then + echo "test_busypoll_with_suspend failed" + cleanup_ns + exit 1 +fi + +echo "$NSIM_SV_FD:$NSIM_SV_IFIDX" > $NSIM_DEV_SYS_UNLINK + +echo $NSIM_CL_ID > $NSIM_DEV_SYS_DEL + +cleanup_ns + +modprobe -r netdevsim + +exit 0 diff --git a/tools/testing/selftests/net/busy_poller.c b/tools/testing/selftests/net/busy_poller.c new file mode 100644 index 000000000000..99b0e8c17fca --- /dev/null +++ b/tools/testing/selftests/net/busy_poller.c @@ -0,0 +1,346 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <assert.h> +#include <errno.h> +#include <error.h> +#include <fcntl.h> +#include <inttypes.h> +#include <limits.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include <ynl.h> + +#include <arpa/inet.h> +#include <netinet/in.h> + +#include <sys/epoll.h> +#include <sys/ioctl.h> +#include <sys/socket.h> +#include <sys/types.h> + +#include <linux/genetlink.h> +#include <linux/netlink.h> + +#include "netdev-user.h" + +/* The below ifdef blob is required because: + * + * - sys/epoll.h does not (yet) have the ioctl definitions included. So, + * systems with older glibcs will not have them available. However, + * sys/epoll.h does include the type definition for epoll_data, which is + * needed by the user program (e.g. epoll_event.data.fd) + * + * - linux/eventpoll.h does not define the epoll_data type, it is simply an + * opaque __u64. It does, however, include the ioctl definition. + * + * Including both headers is impossible (types would be redefined), so I've + * opted instead to take sys/epoll.h, and include the blob below. + * + * Someday, when glibc is globally up to date, the blob below can be removed. + */ +#if !defined(EPOLL_IOC_TYPE) +struct epoll_params { + uint32_t busy_poll_usecs; + uint16_t busy_poll_budget; + uint8_t prefer_busy_poll; + + /* pad the struct to a multiple of 64bits */ + uint8_t __pad; +}; + +#define EPOLL_IOC_TYPE 0x8A +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params) +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params) +#endif + +static uint32_t cfg_port = 8000; +static struct in_addr cfg_bind_addr = { .s_addr = INADDR_ANY }; +static char *cfg_outfile; +static int cfg_max_events = 8; +static int cfg_ifindex; + +/* busy poll params */ +static uint32_t cfg_busy_poll_usecs; +static uint32_t cfg_busy_poll_budget; +static uint32_t cfg_prefer_busy_poll; + +/* IRQ params */ +static uint32_t cfg_defer_hard_irqs; +static uint64_t cfg_gro_flush_timeout; +static uint64_t cfg_irq_suspend_timeout; + +static void usage(const char *filepath) +{ + error(1, 0, + "Usage: %s -p<port> -b<addr> -m<max_events> -u<busy_poll_usecs> -P<prefer_busy_poll> -g<busy_poll_budget> -o<outfile> -d<defer_hard_irqs> -r<gro_flush_timeout> -s<irq_suspend_timeout> -i<ifindex>", + filepath); +} + +static void parse_opts(int argc, char **argv) +{ + int ret; + int c; + + if (argc <= 1) + usage(argv[0]); + + while ((c = getopt(argc, argv, "p:m:b:u:P:g:o:d:r:s:i:")) != -1) { + switch (c) { + case 'u': + cfg_busy_poll_usecs = strtoul(optarg, NULL, 0); + if (cfg_busy_poll_usecs == ULONG_MAX || + cfg_busy_poll_usecs > UINT32_MAX) + error(1, ERANGE, "busy_poll_usecs too large"); + break; + case 'P': + cfg_prefer_busy_poll = strtoul(optarg, NULL, 0); + if (cfg_prefer_busy_poll == ULONG_MAX || + cfg_prefer_busy_poll > 1) + error(1, ERANGE, + "prefer busy poll should be 0 or 1"); + break; + case 'g': + cfg_busy_poll_budget = strtoul(optarg, NULL, 0); + if (cfg_busy_poll_budget == ULONG_MAX || + cfg_busy_poll_budget > UINT16_MAX) + error(1, ERANGE, + "busy poll budget must be [0, UINT16_MAX]"); + break; + case 'p': + cfg_port = strtoul(optarg, NULL, 0); + if (cfg_port > UINT16_MAX) + error(1, ERANGE, "port must be <= 65535"); + break; + case 'b': + ret = inet_aton(optarg, &cfg_bind_addr); + if (ret == 0) + error(1, errno, + "bind address %s invalid", optarg); + break; + case 'o': + cfg_outfile = strdup(optarg); + if (!cfg_outfile) + error(1, 0, "outfile invalid"); + break; + case 'm': + cfg_max_events = strtol(optarg, NULL, 0); + + if (cfg_max_events == LONG_MIN || + cfg_max_events == LONG_MAX || + cfg_max_events <= 0) + error(1, ERANGE, + "max events must be > 0 and < LONG_MAX"); + break; + case 'd': + cfg_defer_hard_irqs = strtoul(optarg, NULL, 0); + + if (cfg_defer_hard_irqs == ULONG_MAX || + cfg_defer_hard_irqs > INT32_MAX) + error(1, ERANGE, + "defer_hard_irqs must be <= INT32_MAX"); + break; + case 'r': + cfg_gro_flush_timeout = strtoull(optarg, NULL, 0); + + if (cfg_gro_flush_timeout == ULLONG_MAX) + error(1, ERANGE, + "gro_flush_timeout must be < ULLONG_MAX"); + break; + case 's': + cfg_irq_suspend_timeout = strtoull(optarg, NULL, 0); + + if (cfg_irq_suspend_timeout == ULLONG_MAX) + error(1, ERANGE, + "irq_suspend_timeout must be < ULLONG_MAX"); + break; + case 'i': + cfg_ifindex = strtoul(optarg, NULL, 0); + if (cfg_ifindex == ULONG_MAX) + error(1, ERANGE, + "ifindex must be < ULONG_MAX"); + break; + } + } + + if (!cfg_ifindex) + usage(argv[0]); + + if (optind != argc) + usage(argv[0]); +} + +static void epoll_ctl_add(int epfd, int fd, uint32_t events) +{ + struct epoll_event ev; + + ev.events = events; + ev.data.fd = fd; + if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev) == -1) + error(1, errno, "epoll_ctl add fd: %d", fd); +} + +static void setnonblock(int sockfd) +{ + int flags; + + flags = fcntl(sockfd, F_GETFL, 0); + + if (fcntl(sockfd, F_SETFL, flags | O_NONBLOCK) == -1) + error(1, errno, "unable to set socket to nonblocking mode"); +} + +static void write_chunk(int fd, char *buf, ssize_t buflen) +{ + ssize_t remaining = buflen; + char *buf_offset = buf; + ssize_t writelen = 0; + ssize_t write_result; + + while (writelen < buflen) { + write_result = write(fd, buf_offset, remaining); + if (write_result == -1) + error(1, errno, "unable to write data to outfile"); + + writelen += write_result; + remaining -= write_result; + buf_offset += write_result; + } +} + +static void setup_queue(void) +{ + struct netdev_napi_get_list *napi_list = NULL; + struct netdev_napi_get_req_dump *req = NULL; + struct netdev_napi_set_req *set_req = NULL; + struct ynl_sock *ys; + struct ynl_error yerr; + uint32_t napi_id; + + ys = ynl_sock_create(&ynl_netdev_family, &yerr); + if (!ys) + error(1, 0, "YNL: %s", yerr.msg); + + req = netdev_napi_get_req_dump_alloc(); + netdev_napi_get_req_dump_set_ifindex(req, cfg_ifindex); + napi_list = netdev_napi_get_dump(ys, req); + + /* assume there is 1 NAPI configured and take the first */ + if (napi_list->obj._present.id) + napi_id = napi_list->obj.id; + else + error(1, 0, "napi ID not present?"); + + set_req = netdev_napi_set_req_alloc(); + netdev_napi_set_req_set_id(set_req, napi_id); + netdev_napi_set_req_set_defer_hard_irqs(set_req, cfg_defer_hard_irqs); + netdev_napi_set_req_set_gro_flush_timeout(set_req, + cfg_gro_flush_timeout); + netdev_napi_set_req_set_irq_suspend_timeout(set_req, + cfg_irq_suspend_timeout); + + if (netdev_napi_set(ys, set_req)) + error(1, 0, "can't set NAPI params: %s\n", yerr.msg); + + netdev_napi_get_list_free(napi_list); + netdev_napi_get_req_dump_free(req); + netdev_napi_set_req_free(set_req); + ynl_sock_destroy(ys); +} + +static void run_poller(void) +{ + struct epoll_event events[cfg_max_events]; + struct epoll_params epoll_params = {0}; + struct sockaddr_in server_addr; + int i, epfd, nfds; + ssize_t readlen; + int outfile_fd; + char buf[1024]; + int sockfd; + int conn; + int val; + + outfile_fd = open(cfg_outfile, O_WRONLY | O_CREAT, 0644); + if (outfile_fd == -1) + error(1, errno, "unable to open outfile: %s", cfg_outfile); + + sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); + if (sockfd == -1) + error(1, errno, "unable to create listen socket"); + + server_addr.sin_family = AF_INET; + server_addr.sin_port = htons(cfg_port); + server_addr.sin_addr = cfg_bind_addr; + + /* these values are range checked during parse_opts, so casting is safe + * here + */ + epoll_params.busy_poll_usecs = cfg_busy_poll_usecs; + epoll_params.busy_poll_budget = (uint16_t)cfg_busy_poll_budget; + epoll_params.prefer_busy_poll = (uint8_t)cfg_prefer_busy_poll; + epoll_params.__pad = 0; + + val = 1; + if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val))) + error(1, errno, "poller setsockopt reuseaddr"); + + setnonblock(sockfd); + + if (bind(sockfd, (struct sockaddr *)&server_addr, + sizeof(struct sockaddr_in))) + error(0, errno, "poller bind to port: %d\n", cfg_port); + + if (listen(sockfd, 1)) + error(1, errno, "poller listen"); + + epfd = epoll_create1(0); + if (ioctl(epfd, EPIOCSPARAMS, &epoll_params) == -1) + error(1, errno, "unable to set busy poll params"); + + epoll_ctl_add(epfd, sockfd, EPOLLIN | EPOLLOUT | EPOLLET); + + for (;;) { + nfds = epoll_wait(epfd, events, cfg_max_events, -1); + for (i = 0; i < nfds; i++) { + if (events[i].data.fd == sockfd) { + conn = accept(sockfd, NULL, NULL); + if (conn == -1) + error(1, errno, + "accepting incoming connection failed"); + + setnonblock(conn); + epoll_ctl_add(epfd, conn, + EPOLLIN | EPOLLET | EPOLLRDHUP | + EPOLLHUP); + } else if (events[i].events & EPOLLIN) { + for (;;) { + readlen = read(events[i].data.fd, buf, + sizeof(buf)); + if (readlen > 0) + write_chunk(outfile_fd, buf, + readlen); + else + break; + } + } else { + /* spurious event ? */ + } + if (events[i].events & (EPOLLRDHUP | EPOLLHUP)) { + epoll_ctl(epfd, EPOLL_CTL_DEL, + events[i].data.fd, NULL); + close(events[i].data.fd); + close(outfile_fd); + return; + } + } + } +} + +int main(int argc, char *argv[]) +{ + parse_opts(argc, argv); + setup_queue(); + run_poller(); + return 0; +} |