From patchwork Wed May 6 10:24:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Phil Yang X-Patchwork-Id: 186244 Delivered-To: patch@linaro.org Received: by 2002:a92:8d81:0:0:0:0:0 with SMTP id w1csp1976927ill; Wed, 6 May 2020 03:25:51 -0700 (PDT) X-Google-Smtp-Source: APiQypJFPM+xdXZL/8PYXS+Mi1VEJabnuKBRxKjntuIF0OMUK3H4RCZ6kj44w+iAtrvHkZxX09H1 X-Received: by 2002:a50:fa87:: with SMTP id w7mr6481780edr.0.1588760751723; Wed, 06 May 2020 03:25:51 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1588760751; cv=none; d=google.com; s=arc-20160816; b=ZP0W+tGQfWhGfKWBEwREHKwUndpg1sSUH1JvXPB2DBZPhtOMUqpRhuYI34cis8URs+ e6M24OLXxZqyj8TwRNb32ZlJ2g6u98/sFSHFNumm581NYJjWNuKOXfcneXbNvxClkvGS QjGoLDvtcO2VonBo4cow8cU+QGYoAJLBX00sqEstNAA/DPtmNEuGZUYmao0zKI6OzDxp 0Op5kbiefEApdHnTHIfanS3wmtSCzLRJ5ApnBoKUIgkhqZhYtuUZRPqGGSBvFAOFxCaq N8YrTf7ZqUX7e2seG8ubfaDLLxqV7rVfGW1xyQzQZ+vzGHpzQ82yOxn12OaIVfNt5zy0 mSbQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:cc:to:from; bh=Vo4V77ZYV/N5/nIF2XQiIHeLduLaL/vvmw91zios+O0=; b=1E5BUSl8M2o0rjjdwoiIoy2CebDIMtaBmnOIrT97qDIa9PpqO3lknn6ylzaIohDXEp T3tQCXY3GHu9+qKse1h45mBI24NyBsUUFDESdgdJYHhvHTMSsutMABoKuAdbR1fyfV6m OYiGskDNw0L3LoNZuVqUnIGC3ErLTPJvAfcXuOJY6A+tnhi06M/kTcUpSwrWqLE00fiF C3ns4+roqQe22mevvYDfTHgQnwGXxSdF/jJGy3Lj15SHanOU1fDqeeWgU8ooCAuXVUTB 7evv6aYjK9mXXimEVGtWitNEoFSW33ETttipgu+AVOXW+PRiWn2ll2WKoTNr0lbj7exc 1MrQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id r17si766218edy.222.2020.05.06.03.25.51; Wed, 06 May 2020 03:25:51 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 5FEB11D8F6; Wed, 6 May 2020 12:25:51 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 522ED1D8F4; Wed, 6 May 2020 12:25:50 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C6F1E30E; Wed, 6 May 2020 03:25:49 -0700 (PDT) Received: from phil-VirtualBox.shanghai.arm.com (phil-VirtualBox.shanghai.arm.com [10.169.108.145]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 70F4B3F71F; Wed, 6 May 2020 03:25:46 -0700 (PDT) From: Phil Yang To: dev@dpdk.org, harry.van.haaren@intel.com Cc: thomas@monjalon.net, david.marchand@redhat.com, konstantin.ananyev@intel.com, jerinj@marvell.com, hemant.agrawal@nxp.com, gage.eads@intel.com, bruce.richardson@intel.com, Honnappa.Nagarahalli@arm.com, nd@arm.com, Honnappa Nagarahalli , stable@dpdk.org Date: Wed, 6 May 2020 18:24:38 +0800 Message-Id: <1588760683-11027-2-git-send-email-phil.yang@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1588760683-11027-1-git-send-email-phil.yang@arm.com> References: <20200505211732.25291-1-honnappa.nagarahalli@arm.com> <1588760683-11027-1-git-send-email-phil.yang@arm.com> Subject: [dpdk-dev] [PATCH v5 1/6] service: fix race condition for MT unsafe service X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" From: Honnappa Nagarahalli The MT unsafe service might get configured to run on another core while the service is running currently. This might result in the MT unsafe service running on multiple cores simultaneously. Use 'execute_lock' always when the service is MT unsafe. If the service is known to be mmapped on a single lcore, setting the service capability to MT safe will avoid taking the lock and improve the performance. Fixes: e9139a32f6e8 ("service: add function to run on app lcore") Cc: stable@dpdk.org Signed-off-by: Honnappa Nagarahalli Reviewed-by: Phil Yang Acked-by: Harry van Haaren --- lib/librte_eal/common/rte_service.c | 11 +++++------ lib/librte_eal/include/rte_service.h | 8 ++++++-- lib/librte_eal/include/rte_service_component.h | 6 +++++- 3 files changed, 16 insertions(+), 9 deletions(-) -- 2.7.4 diff --git a/lib/librte_eal/common/rte_service.c b/lib/librte_eal/common/rte_service.c index 70d17a5..b8c465e 100644 --- a/lib/librte_eal/common/rte_service.c +++ b/lib/librte_eal/common/rte_service.c @@ -50,6 +50,10 @@ struct rte_service_spec_impl { uint8_t internal_flags; /* per service statistics */ + /* Indicates how many cores the service is mapped to run on. + * It does not indicate the number of cores the service is running + * on currently. + */ rte_atomic32_t num_mapped_cores; uint64_t calls; uint64_t cycles_spent; @@ -370,12 +374,7 @@ service_run(uint32_t i, struct core_state *cs, uint64_t service_mask, cs->service_active_on_lcore[i] = 1; - /* check do we need cmpset, if MT safe or <= 1 core - * mapped, atomic ops are not required. - */ - const int use_atomics = (service_mt_safe(s) == 0) && - (rte_atomic32_read(&s->num_mapped_cores) > 1); - if (use_atomics) { + if (service_mt_safe(s) == 0) { if (!rte_atomic32_cmpset((uint32_t *)&s->execute_lock, 0, 1)) return -EBUSY; diff --git a/lib/librte_eal/include/rte_service.h b/lib/librte_eal/include/rte_service.h index d8701dd..3a1c735 100644 --- a/lib/librte_eal/include/rte_service.h +++ b/lib/librte_eal/include/rte_service.h @@ -104,12 +104,16 @@ int32_t rte_service_probe_capability(uint32_t id, uint32_t capability); * Each core can be added or removed from running a specific service. This * function enables or disables *lcore* to run *service_id*. * - * If multiple cores are enabled on a service, an atomic is used to ensure that - * only one cores runs the service at a time. The exception to this is when + * If multiple cores are enabled on a service, a lock is used to ensure that + * only one core runs the service at a time. The exception to this is when * a service indicates that it is multi-thread safe by setting the capability * called RTE_SERVICE_CAP_MT_SAFE. With the multi-thread safe capability set, * the service function can be run on multiple threads at the same time. * + * If the service is known to be mapped to a single lcore, setting the + * capability of the service to RTE_SERVICE_CAP_MT_SAFE can achieve + * better performance by avoiding the use of lock. + * * @param service_id the service to apply the lcore to * @param lcore The lcore that will be mapped to service * @param enable Zero to unmap or disable the core, non-zero to enable diff --git a/lib/librte_eal/include/rte_service_component.h b/lib/librte_eal/include/rte_service_component.h index 16eab79..b75aba1 100644 --- a/lib/librte_eal/include/rte_service_component.h +++ b/lib/librte_eal/include/rte_service_component.h @@ -43,7 +43,7 @@ struct rte_service_spec { /** * Register a new service. * - * A service represents a component that the requires CPU time periodically to + * A service represents a component that requires CPU time periodically to * achieve its purpose. * * For example the eventdev SW PMD requires CPU cycles to perform its @@ -56,6 +56,10 @@ struct rte_service_spec { * *rte_service_component_runstate_set*, which indicates that the service * component is ready to be executed. * + * If the service is known to be mapped to a single lcore, setting the + * capability of the service to RTE_SERVICE_CAP_MT_SAFE can achieve + * better performance. + * * @param spec The specification of the service to register * @param[out] service_id A pointer to a uint32_t, which will be filled in * during registration of the service. It is set to the integers From patchwork Wed May 6 10:24:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Phil Yang X-Patchwork-Id: 186245 Delivered-To: patch@linaro.org Received: by 2002:a92:8d81:0:0:0:0:0 with SMTP id w1csp1977037ill; Wed, 6 May 2020 03:26:00 -0700 (PDT) X-Google-Smtp-Source: APiQypIOdk9qNaxNu9ErfNq2y0bA37cG47Vt7qdBaDhsdSCbvBirqYRo5b4rWtESbW4zRFyhpt8w X-Received: by 2002:a50:ef18:: with SMTP id m24mr6098343eds.281.1588760760574; Wed, 06 May 2020 03:26:00 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1588760760; cv=none; d=google.com; s=arc-20160816; b=GeFNpVW8AveEzqaeqD983yl0aKrsmVvdsyROjX1V7avLYhKZbrxLkTKfigDTNJLFwH fHF/xkOSIVUsUXek98OfUk+gnwvT696PYOmYoymT/HGe7Dn41yce3kSdAGtE/ZrRfO8o rPD/jJeBPkUOjXGHvK6k4PKTAOBKJThmpWaoSbQQriEzpie+rggYiJgqo4BtYhvZLyat ea7gDoubqss1V1Lzdd0WF8VQcf/faWZ9yDbIfP6LsEEVcnHKuDKeIVNhXvodJImL9P5A 4nEza+jVYi9HnSp6LU9kvPhDZjO+VJyEFj18D3bPCisO0nvZA+FPQUFYF5sGGIsrzdVr 328g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:cc:to:from; bh=XyTHIG8Yut73x3x/VmRXUpkJ2sjyF1Tfn/QgMrfIhh0=; b=1Hj7gQoGYKqbR2ccJnWGozS+894M8sGXnqSzpOHhIgvpgs/5EX4EX0AIufMc5XsWKd 8fWo6o9vBFE9mGQCB6YegqRG+hH1VOZSzYoPo6NG6BjUsuCrKwz4fzfLGlXyjJu5lQIw 3ci/HNQhPodsdp4mlCmzRycGx2EGhxhuY2eaDyC9Mw5dD2HDzomblciSoFC6Mkmts3N0 2rdEqCjff8x1QvyibgIgGNi6ChZiYGQDATw4RDZaX5kC+kfvgfXGecNtLYsP/P/hL36Q +T8Idk0th+yln1EKO2eJRm0uZy77PvjgmmTUe3VO7SSj0HmID2qUjBso9eRAOr4SGSal ZKpg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id d20si792283edz.32.2020.05.06.03.26.00; Wed, 06 May 2020 03:26:00 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id ED6D71D907; Wed, 6 May 2020 12:25:57 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id BF5F81D8FF; Wed, 6 May 2020 12:25:56 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 47FD130E; Wed, 6 May 2020 03:25:56 -0700 (PDT) Received: from phil-VirtualBox.shanghai.arm.com (phil-VirtualBox.shanghai.arm.com [10.169.108.145]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id DCFF93F71F; Wed, 6 May 2020 03:25:52 -0700 (PDT) From: Phil Yang To: dev@dpdk.org, harry.van.haaren@intel.com Cc: thomas@monjalon.net, david.marchand@redhat.com, konstantin.ananyev@intel.com, jerinj@marvell.com, hemant.agrawal@nxp.com, gage.eads@intel.com, bruce.richardson@intel.com, Honnappa.Nagarahalli@arm.com, nd@arm.com, Honnappa Nagarahalli , stable@dpdk.org Date: Wed, 6 May 2020 18:24:39 +0800 Message-Id: <1588760683-11027-3-git-send-email-phil.yang@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1588760683-11027-1-git-send-email-phil.yang@arm.com> References: <20200505211732.25291-1-honnappa.nagarahalli@arm.com> <1588760683-11027-1-git-send-email-phil.yang@arm.com> Subject: [dpdk-dev] [PATCH v5 2/6] service: fix identification of service running on other lcore X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" From: Honnappa Nagarahalli The logic to identify if the MT unsafe service is running on another core can return -EBUSY spuriously. In such cases, running the service becomes costlier than using atomic operations. Assume that the application passes the right parameters and reduce the number of instructions for all cases. Cc: stable@dpdk.org Fixes: 8d39d3e237c2 ("service: fix race in service on app lcore function") Signed-off-by: Honnappa Nagarahalli Reviewed-by: Phil Yang Acked-by: Harry van Haaren --- lib/librte_eal/common/rte_service.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-) -- 2.7.4 diff --git a/lib/librte_eal/common/rte_service.c b/lib/librte_eal/common/rte_service.c index b8c465e..c283408 100644 --- a/lib/librte_eal/common/rte_service.c +++ b/lib/librte_eal/common/rte_service.c @@ -360,7 +360,7 @@ rte_service_runner_do_callback(struct rte_service_spec_impl *s, /* Expects the service 's' is valid. */ static int32_t service_run(uint32_t i, struct core_state *cs, uint64_t service_mask, - struct rte_service_spec_impl *s) + struct rte_service_spec_impl *s, uint32_t serialize_mt_unsafe) { if (!s) return -EINVAL; @@ -374,7 +374,7 @@ service_run(uint32_t i, struct core_state *cs, uint64_t service_mask, cs->service_active_on_lcore[i] = 1; - if (service_mt_safe(s) == 0) { + if ((service_mt_safe(s) == 0) && (serialize_mt_unsafe == 1)) { if (!rte_atomic32_cmpset((uint32_t *)&s->execute_lock, 0, 1)) return -EBUSY; @@ -412,24 +412,14 @@ rte_service_run_iter_on_app_lcore(uint32_t id, uint32_t serialize_mt_unsafe) SERVICE_VALID_GET_OR_ERR_RET(id, s, -EINVAL); - /* Atomically add this core to the mapped cores first, then examine if - * we can run the service. This avoids a race condition between - * checking the value, and atomically adding to the mapped count. + /* Increment num_mapped_cores to reflect that this core is + * now mapped capable of running the service. */ - if (serialize_mt_unsafe) - rte_atomic32_inc(&s->num_mapped_cores); + rte_atomic32_inc(&s->num_mapped_cores); - if (service_mt_safe(s) == 0 && - rte_atomic32_read(&s->num_mapped_cores) > 1) { - if (serialize_mt_unsafe) - rte_atomic32_dec(&s->num_mapped_cores); - return -EBUSY; - } - - int ret = service_run(id, cs, UINT64_MAX, s); + int ret = service_run(id, cs, UINT64_MAX, s, serialize_mt_unsafe); - if (serialize_mt_unsafe) - rte_atomic32_dec(&s->num_mapped_cores); + rte_atomic32_dec(&s->num_mapped_cores); return ret; } @@ -449,7 +439,7 @@ rte_service_runner_func(void *arg) if (!service_valid(i)) continue; /* return value ignored as no change to code flow */ - service_run(i, cs, service_mask, service_get(i)); + service_run(i, cs, service_mask, service_get(i), 1); } cs->loops++;