From patchwork Wed Dec 9 15:03:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Loic Poulain X-Patchwork-Id: 1413477 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=oB8cX+Z4; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4Crg9k6nK9z9sVq for ; Thu, 10 Dec 2020 01:56:42 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733221AbgLIO4l (ORCPT ); Wed, 9 Dec 2020 09:56:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732558AbgLIO4l (ORCPT ); Wed, 9 Dec 2020 09:56:41 -0500 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 03739C0613CF for ; Wed, 9 Dec 2020 06:56:01 -0800 (PST) Received: by mail-wr1-x444.google.com with SMTP id i9so2065995wrc.4 for ; Wed, 09 Dec 2020 06:56:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=DvbvG6mQGm3snXcxs0szgugtcoGkSBwdHyd4ZKjZrVE=; b=oB8cX+Z4rNWyS4GCSBB/ODF7O05C4eQUADsbe2lrGqcdXoTFeqmv0cr+zaiHT8Ozpd ja3YSzbYRXWWLfMIvVIlnQKC5cGHMtSaqzUHqmSQLwnlAPnYZLvYSfP5nfSCItu/uMe5 QicDJlzLCj10J5iZFEuiJ4jMSNuqkAt+kQ6+5d7JXhfk1zsdyp+9rkZ1llgrGZfms/qw 2zDxF1GU049XQUfxzKX8URR6CqvdIjhUr+92PJPPxMs44PlQeYxNy5QKN9uFahftV8E5 WWA+tz2y+TiiIqg5QqlrR0iWuX3sBh78XmSRKuz+LWOvcNLeZQCVdBhE4PrWlps0rsXQ XBnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=DvbvG6mQGm3snXcxs0szgugtcoGkSBwdHyd4ZKjZrVE=; b=didVpMnIjewQZbU8qeWXrl+T28m94o30twf/bOGH4OYc5i+9heZWvHeZczw0I9AqRl 0vb/NKj3U36CgrTNmD5kMM+mIOFr5tV6EZTwGBWJaGaOmWMpGUGbVP9m4AHiBexrgvMf q/UECOfpRVORsHbQUEV8V7ik7HAjzGk8Y6QPPP+Dg1FRZWkSI+/ePTTkhUaoiEDYYMtd 4gYz/PxbBPbjRn57xnStxR4oiwDXxMhzFzjxC/9Lxg0kFS0jQ79ostaVKSbfluarnYYI aCiLKC07B6BJqgM3MxG2R35FoQWS0SswUb79poryWcuaBiDUSzud+Jtbk40k4L+fKw6E +CKg== X-Gm-Message-State: AOAM530C0F8pA/qSUOc2cBH57USbXBtZUiRm5z7AQ46Q/ZzPSGAsMoX0 ex48h1lLxFpPXLOGBedwDsTQSoBcmymhEpbV X-Google-Smtp-Source: ABdhPJyXtOpUmw7LcWmrd+o1rvAd+cU6WaHd2Ay85/a7Q5EWljbi+Y/+LpQK+VhbCaTiH62+JIMX2w== X-Received: by 2002:adf:ed12:: with SMTP id a18mr3132543wro.5.1607525759683; Wed, 09 Dec 2020 06:55:59 -0800 (PST) Received: from localhost.localdomain ([2a01:e0a:490:8730:c728:53f6:5e7e:2f63]) by smtp.gmail.com with ESMTPSA id i11sm3782219wrm.1.2020.12.09.06.55.58 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Dec 2020 06:55:59 -0800 (PST) From: Loic Poulain To: kuba@kernel.org Cc: manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, Hemant Kumar Subject: [PATCH 1/3] bus: mhi: core: Add helper API to return number of free TREs Date: Wed, 9 Dec 2020 16:03:01 +0100 Message-Id: <1607526183-25652-1-git-send-email-loic.poulain@linaro.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Hemant Kumar Introduce mhi_get_free_desc_count() API to return number of TREs available to queue buffer. MHI clients can use this API to know before hand if ring is full without calling queue API. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo Reviewed-by: Manivannan Sadhasivam --- drivers/bus/mhi/core/main.c | 12 ++++++++++++ include/linux/mhi.h | 9 +++++++++ 2 files changed, 21 insertions(+) diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index 54d9c80..a24ba4f 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -303,6 +303,18 @@ int mhi_destroy_device(struct device *dev, void *data) return 0; } +int mhi_get_free_desc_count(struct mhi_device *mhi_dev, + enum dma_data_direction dir) +{ + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; + struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ? + mhi_dev->ul_chan : mhi_dev->dl_chan; + struct mhi_ring *tre_ring = &mhi_chan->tre_ring; + + return get_nr_avail_ring_elements(mhi_cntrl, tre_ring); +} +EXPORT_SYMBOL_GPL(mhi_get_free_desc_count); + void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason) { struct mhi_driver *mhi_drv; diff --git a/include/linux/mhi.h b/include/linux/mhi.h index 09f786e..25c69a0 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -616,6 +616,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl, void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason); /** + * mhi_get_free_desc_count - Get transfer ring length + * Get # of TD available to queue buffers + * @mhi_dev: Device associated with the channels + * @dir: Direction of the channel + */ +int mhi_get_free_desc_count(struct mhi_device *mhi_dev, + enum dma_data_direction dir); + +/** * mhi_prepare_for_power_up - Do pre-initialization before power up. * This is optional, call this before power up if * the controller does not want bus framework to From patchwork Wed Dec 9 15:03:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Loic Poulain X-Patchwork-Id: 1413478 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: ozlabs.org; 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Wed, 09 Dec 2020 06:56:01 -0800 (PST) Received: from localhost.localdomain ([2a01:e0a:490:8730:c728:53f6:5e7e:2f63]) by smtp.gmail.com with ESMTPSA id i11sm3782219wrm.1.2020.12.09.06.56.01 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Dec 2020 06:56:01 -0800 (PST) From: Loic Poulain To: kuba@kernel.org Cc: manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, Loic Poulain Subject: [PATCH 2/3] net: mhi: Get RX queue size from MHI core Date: Wed, 9 Dec 2020 16:03:02 +0100 Message-Id: <1607526183-25652-2-git-send-email-loic.poulain@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1607526183-25652-1-git-send-email-loic.poulain@linaro.org> References: <1607526183-25652-1-git-send-email-loic.poulain@linaro.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The RX queue size can be determined at runtime by retrieveing the number of available transfer descriptors Signed-off-by: Loic Poulain --- drivers/net/mhi_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c index 8e72d94..0333e07 100644 --- a/drivers/net/mhi_net.c +++ b/drivers/net/mhi_net.c @@ -256,9 +256,6 @@ static int mhi_net_probe(struct mhi_device *mhi_dev, mhi_netdev->mdev = mhi_dev; SET_NETDEV_DEV(ndev, &mhi_dev->dev); - /* All MHI net channels have 128 ring elements (at least for now) */ - mhi_netdev->rx_queue_sz = 128; - INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work); u64_stats_init(&mhi_netdev->stats.rx_syncp); u64_stats_init(&mhi_netdev->stats.tx_syncp); @@ -268,6 +265,9 @@ static int mhi_net_probe(struct mhi_device *mhi_dev, if (err) goto out_err; + /* Number of transfer descriptors determines size of the queue */ + mhi_netdev->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + err = register_netdev(ndev); if (err) goto out_err; From patchwork Wed Dec 9 15:03:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Loic Poulain X-Patchwork-Id: 1413480 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; 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Wed, 09 Dec 2020 06:56:03 -0800 (PST) Received: from localhost.localdomain ([2a01:e0a:490:8730:c728:53f6:5e7e:2f63]) by smtp.gmail.com with ESMTPSA id i11sm3782219wrm.1.2020.12.09.06.56.02 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Dec 2020 06:56:03 -0800 (PST) From: Loic Poulain To: kuba@kernel.org Cc: manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, Loic Poulain Subject: [PATCH 3/3] net: mhi: Add dedicated alloc thread Date: Wed, 9 Dec 2020 16:03:03 +0100 Message-Id: <1607526183-25652-3-git-send-email-loic.poulain@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1607526183-25652-1-git-send-email-loic.poulain@linaro.org> References: <1607526183-25652-1-git-send-email-loic.poulain@linaro.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The buffer allocation for RX path is currently done by a work executed in the system workqueue. The work to do is quite simple and consists mostly in allocating and queueing as much as possible buffers to the MHI RX channel. It appears that using a dedicated kthread would be more appropriate to prevent 1. RX allocation latency introduced by the system queue 2. Unbounded work execution, the work only returning when queue is full, it can possibly monopolise the workqueue thread on slower systems. This patch replaces the system work with a simple kthread that loops on buffer allocation and sleeps when queue is full. Moreover it gets rid of the local rx_queued variable (to track buffer count), and instead, relies on the new mhi_get_free_desc_count helper. After pratical testing on a x86_64 machine, this change improves - Peek throughput (slightly, by few mbps) - Throughput stability when concurrent loads are running (stress) - CPU usage, less CPU cycles dedicated to the task Below is the powertop output for RX allocation task before and after this change, when performing UDP download at 6Gbps. Mostly to highlight the improvement in term of CPU usage. older (system workqueue): Usage Events/s Category Description 63,2 ms/s 134,0 kWork mhi_net_rx_refill_work 62,8 ms/s 134,3 kWork mhi_net_rx_refill_work 60,8 ms/s 141,4 kWork mhi_net_rx_refill_work newer (dedicated kthread): Usage Events/s Category Description 20,7 ms/s 155,6 Process [PID 3360] [mhi-net-rx] 22,2 ms/s 169,6 Process [PID 3360] [mhi-net-rx] 22,3 ms/s 150,2 Process [PID 3360] [mhi-net-rx] Signed-off-by: Loic Poulain --- drivers/net/mhi_net.c | 98 ++++++++++++++++++++++++++------------------------- 1 file changed, 50 insertions(+), 48 deletions(-) diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c index 0333e07..eef40f5 100644 --- a/drivers/net/mhi_net.c +++ b/drivers/net/mhi_net.c @@ -5,6 +5,7 @@ */ #include +#include #include #include #include @@ -25,7 +26,6 @@ struct mhi_net_stats { u64_stats_t tx_bytes; u64_stats_t tx_errors; u64_stats_t tx_dropped; - atomic_t rx_queued; struct u64_stats_sync tx_syncp; struct u64_stats_sync rx_syncp; }; @@ -33,17 +33,59 @@ struct mhi_net_stats { struct mhi_net_dev { struct mhi_device *mdev; struct net_device *ndev; - struct delayed_work rx_refill; + struct task_struct *refill_task; + wait_queue_head_t refill_wq; struct mhi_net_stats stats; u32 rx_queue_sz; }; +static int mhi_net_refill_thread(void *data) +{ + struct mhi_net_dev *mhi_netdev = data; + struct net_device *ndev = mhi_netdev->ndev; + struct mhi_device *mdev = mhi_netdev->mdev; + int size = READ_ONCE(ndev->mtu); + struct sk_buff *skb; + int err; + + while (1) { + err = wait_event_interruptible(mhi_netdev->refill_wq, + !mhi_queue_is_full(mdev, DMA_FROM_DEVICE) + || kthread_should_stop()); + if (err || kthread_should_stop()) + break; + + skb = netdev_alloc_skb(ndev, size); + if (unlikely(!skb)) { + /* No memory, retry later */ + schedule_timeout_interruptible(msecs_to_jiffies(250)); + continue; + } + + err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT); + if (unlikely(err)) { + net_err_ratelimited("%s: Failed to queue RX buf (%d)\n", + ndev->name, err); + kfree_skb(skb); + break; + } + + /* Do not hog the CPU */ + cond_resched(); + } + + return 0; +} + static int mhi_ndo_open(struct net_device *ndev) { struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); - /* Feed the rx buffer pool */ - schedule_delayed_work(&mhi_netdev->rx_refill, 0); + mhi_netdev->refill_task = kthread_run(mhi_net_refill_thread, mhi_netdev, + "mhi-net-rx"); + if (IS_ERR(mhi_netdev->refill_task)) { + return PTR_ERR(mhi_netdev->refill_task); + } /* Carrier is established via out-of-band channel (e.g. qmi) */ netif_carrier_on(ndev); @@ -57,9 +99,9 @@ static int mhi_ndo_stop(struct net_device *ndev) { struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + kthread_stop(mhi_netdev->refill_task); netif_stop_queue(ndev); netif_carrier_off(ndev); - cancel_delayed_work_sync(&mhi_netdev->rx_refill); return 0; } @@ -138,9 +180,6 @@ static void mhi_net_dl_callback(struct mhi_device *mhi_dev, { struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev); struct sk_buff *skb = mhi_res->buf_addr; - int remaining; - - remaining = atomic_dec_return(&mhi_netdev->stats.rx_queued); if (unlikely(mhi_res->transaction_status)) { dev_kfree_skb_any(skb); @@ -163,9 +202,8 @@ static void mhi_net_dl_callback(struct mhi_device *mhi_dev, netif_rx(skb); } - /* Refill if RX buffers queue becomes low */ - if (remaining <= mhi_netdev->rx_queue_sz / 2) - schedule_delayed_work(&mhi_netdev->rx_refill, 0); + if (mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE) >= mhi_netdev->rx_queue_sz / 3) + wake_up_interruptible(&mhi_netdev->refill_wq); } static void mhi_net_ul_callback(struct mhi_device *mhi_dev, @@ -200,42 +238,6 @@ static void mhi_net_ul_callback(struct mhi_device *mhi_dev, netif_wake_queue(ndev); } -static void mhi_net_rx_refill_work(struct work_struct *work) -{ - struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev, - rx_refill.work); - struct net_device *ndev = mhi_netdev->ndev; - struct mhi_device *mdev = mhi_netdev->mdev; - int size = READ_ONCE(ndev->mtu); - struct sk_buff *skb; - int err; - - while (atomic_read(&mhi_netdev->stats.rx_queued) < mhi_netdev->rx_queue_sz) { - skb = netdev_alloc_skb(ndev, size); - if (unlikely(!skb)) - break; - - err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT); - if (unlikely(err)) { - net_err_ratelimited("%s: Failed to queue RX buf (%d)\n", - ndev->name, err); - kfree_skb(skb); - break; - } - - atomic_inc(&mhi_netdev->stats.rx_queued); - - /* Do not hog the CPU if rx buffers are consumed faster than - * queued (unlikely). - */ - cond_resched(); - } - - /* If we're still starved of rx buffers, reschedule later */ - if (unlikely(!atomic_read(&mhi_netdev->stats.rx_queued))) - schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2); -} - static int mhi_net_probe(struct mhi_device *mhi_dev, const struct mhi_device_id *id) { @@ -256,7 +258,7 @@ static int mhi_net_probe(struct mhi_device *mhi_dev, mhi_netdev->mdev = mhi_dev; SET_NETDEV_DEV(ndev, &mhi_dev->dev); - INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work); + init_waitqueue_head(&mhi_netdev->refill_wq); u64_stats_init(&mhi_netdev->stats.rx_syncp); u64_stats_init(&mhi_netdev->stats.tx_syncp);