From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96A27C433ED for ; Sun, 18 Apr 2021 13:17:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AA57610E7 for ; Sun, 18 Apr 2021 13:17:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229702AbhDRNSK (ORCPT ); Sun, 18 Apr 2021 09:18:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229671AbhDRNSK (ORCPT ); Sun, 18 Apr 2021 09:18:10 -0400 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67235C06174A for ; Sun, 18 Apr 2021 06:17:40 -0700 (PDT) Received: by mail-ed1-x530.google.com with SMTP id j7so592538eds.8 for ; Sun, 18 Apr 2021 06:17:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=ytsGpC789Qj444BG8Jc3Cth3L8ENInp9vZ5TCibllqE=; b=VktEjKzAh9hUiEDxnAq2NFGKavl0h7peVruSBKASis93l3D/1iYl5XH9k5nRlEFIGo U+Cu9Ung+bYNnM7XM9Wm8oWN1lz5VJdQi1ytAbo4pj1X82su4tkTKxv+2GoTObVFd3ao VXEf1gjgaecGSrXgWvCqDfSoVE12BLjjsiJmu0V+a4a9AuzSeFR1M9V9rtMMIOOOPTDs 4K2f++NzJ7VsPMOO7nMXXvAC5u7cwmZ9N+17lMngj3HJ+gz+FFngz1+Avn/a6FX7oIn5 ADO32iwzZWZ4RYscknw6FKlFv1EfLscIXRIaLar8Jib/v54EdcWIoTy1KOgVk4Lfnmtp 8c3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ytsGpC789Qj444BG8Jc3Cth3L8ENInp9vZ5TCibllqE=; b=Dcl2Ib/AXvwJNZT03pDgBs7xXU00PpjtCFb9MKBxS6Y/DjsY4voJcXIfCnRJt2dBgp GYajU6RiIikT+c+dMvQOn7hkiNHIJAZg3VspV0eBJTxzow6ejpPIQnX314yYzL/kMt9f rOx3aJJzfJH1GprZLZPDw+Xzh+bjcrTs5uJhi6aWPAG26enJ+mwg+NaChUoQDZnNBDXc HQgwgzQTw0uJzoLfY8CA/jbI5F5f0maXpQn3Fef4qThn6ncd3wfA2K7rfWt/VWdots+U UkyT9rHNfLP4RL7auTbQDw4RKlsf5lVVRXc7qasB/mTgVJsyEvRzf6/XJQ7JGa1BeV4w tHlA== X-Gm-Message-State: AOAM533IFdmr289okkd6+WEjE617ekYerQ8sTmWUj/la/TqN8d07qE7g PLGg2Y9XuBPLIQlUpT9fO2CmYCkeYeeVow== X-Google-Smtp-Source: ABdhPJxSmBVayl8UkOag7prruu0zzYNV60zV/49akfGUg5v9YNfsEt55YC3/E/9pRb7i+9YNdaaV9w== X-Received: by 2002:a05:6402:37a:: with SMTP id s26mr1876944edw.159.1618751859130; Sun, 18 Apr 2021 06:17:39 -0700 (PDT) Received: from [192.168.0.108] ([77.124.61.96]) by smtp.gmail.com with ESMTPSA id q10sm6952562eds.26.2021.04.18.06.17.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 18 Apr 2021 06:17:38 -0700 (PDT) Subject: Re: [PATCH] net/mlx4: Treat VFs fair when handling comm_channel_events To: Hans Westgaard Ry , linux-rdma@vger.kernel.org Cc: Jack Morgenstein References: <1618487022-15770-1-git-send-email-hans.westgaard.ry@oracle.com> From: Tariq Toukan Message-ID: Date: Sun, 18 Apr 2021 16:17:36 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <1618487022-15770-1-git-send-email-hans.westgaard.ry@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 4/15/2021 2:43 PM, Hans Westgaard Ry wrote: > Handling comm_channel_event in mlx4_master_comm_channel uses a double > loop to determine which slaves have requested work. The search is > always started at lowest slave. This leads to unfairness; lower VFs > tends to be prioritized over higher VFs. > > The patch uses find_next_bit to determine which slaves to handle. > Fairness is implemented by always starting at the next to the last > start. > > An MPI program has been used to measure improvements. It runs 500 > ibv_reg_mr, synchronizes with all other instances and then runs 500 > ibv_dereg_mr. > > The results running 500 processes, time reported is for running 500 > calls: > > ibv_reg_mr: > Mod. Org. > mlx4_1 403.356ms 424.674ms > mlx4_2 403.355ms 424.674ms > mlx4_3 403.354ms 424.674ms > mlx4_4 403.355ms 424.674ms > mlx4_5 403.357ms 424.677ms > mlx4_6 403.354ms 424.676ms > mlx4_7 403.357ms 424.675ms > mlx4_8 403.355ms 424.675ms > > ibv_dereg_mr: > Mod. Org. > mlx4_1 116.408ms 142.818ms > mlx4_2 116.434ms 142.793ms > mlx4_3 116.488ms 143.247ms > mlx4_4 116.679ms 143.230ms > mlx4_5 112.017ms 107.204ms > mlx4_6 112.032ms 107.516ms > mlx4_7 112.083ms 184.195ms > mlx4_8 115.089ms 190.618ms > > Suggested-by: Håkon Bugge > Signed-off-by: Hans Westgaard Ry > --- > drivers/net/ethernet/mellanox/mlx4/cmd.c | 75 +++++++++++++++++-------------- > drivers/net/ethernet/mellanox/mlx4/mlx4.h | 1 + > 2 files changed, 43 insertions(+), 33 deletions(-) > > diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c > index c678344d22a2..24989e96ab9d 100644 > --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c > +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c > @@ -51,7 +51,6 @@ > #include "fw.h" > #include "fw_qos.h" > #include "mlx4_stats.h" > - > #define CMD_POLL_TOKEN 0xffff > #define INBOX_MASK 0xffffffffffffff00ULL > Unrelated change. Please revert it. > @@ -2241,48 +2240,58 @@ void mlx4_master_comm_channel(struct work_struct *work) > struct mlx4_priv *priv = > container_of(mfunc, struct mlx4_priv, mfunc); > struct mlx4_dev *dev = &priv->dev; > - __be32 *bit_vec; > u32 comm_cmd; > - u32 vec; > - int i, j, slave; > + int i, slave; > int toggle; > int served = 0; > int reported = 0; > u32 slt; > - > - bit_vec = master->comm_arm_bit_vector; > - for (i = 0; i < COMM_CHANNEL_BIT_ARRAY_SIZE; i++) { > - vec = be32_to_cpu(bit_vec[i]); > - for (j = 0; j < 32; j++) { > - if (!(vec & (1 << j))) > - continue; > - ++reported; > - slave = (i * 32) + j; > - comm_cmd = swab32(readl( > - &mfunc->comm[slave].slave_write)); > - slt = swab32(readl(&mfunc->comm[slave].slave_read)) > - >> 31; > - toggle = comm_cmd >> 31; > - if (toggle != slt) { > - if (master->slave_state[slave].comm_toggle > - != slt) { > - pr_info("slave %d out of sync. read toggle %d, state toggle %d. Resynching.\n", > - slave, slt, > - master->slave_state[slave].comm_toggle); > - master->slave_state[slave].comm_toggle = > - slt; > - } > - mlx4_master_do_cmd(dev, slave, > - comm_cmd >> 16 & 0xff, > - comm_cmd & 0xffff, toggle); > - ++served; > + u32 lbit_vec[COMM_CHANNEL_BIT_ARRAY_SIZE]; > + u32 nmbr_bits; > + u32 prev_slave; > + bool first = true; Please maintain reversed Christmas tree when possible. Split declaration from init if needed. > + > + for (i = 0; i < COMM_CHANNEL_BIT_ARRAY_SIZE; i++) > + lbit_vec[i] = be32_to_cpu(master->comm_arm_bit_vector[i]); > + nmbr_bits = dev->persist->num_vfs + 1; > + if (++priv->next_slave >= nmbr_bits) > + priv->next_slave = 0; > + slave = priv->next_slave; > + while (true) { > + slave = find_next_bit((const unsigned long *)&lbit_vec, nmbr_bits, slave); > + if (!first && slave >= priv->next_slave) { > + break; > + } else if (slave == nmbr_bits) { Unnecessary else, as if block breaks. > + if (!first) > + break; > + first = false; > + slave = 0; > + continue; > + } > + ++reported; > + comm_cmd = swab32(readl(&mfunc->comm[slave].slave_write)); > + slt = swab32(readl(&mfunc->comm[slave].slave_read)) >> 31; > + toggle = comm_cmd >> 31; > + if (toggle != slt) { > + if (master->slave_state[slave].comm_toggle > + != slt) { > + pr_info("slave %d out of sync. read toggle %d, state toggle %d. Resynching.\n", > + slave, slt, > + master->slave_state[slave].comm_toggle); > + master->slave_state[slave].comm_toggle = > + slt; > } > + mlx4_master_do_cmd(dev, slave, > + comm_cmd >> 16 & 0xff, > + comm_cmd & 0xffff, toggle); > + ++served; > } > + prev_slave = slave++; > } > > if (reported && reported != served) > - mlx4_warn(dev, "Got command event with bitmask from %d slaves but %d were served\n", > - reported, served); > + mlx4_warn(dev, "Got command event with bitmask from %d slaves but %d were served %x %d\n", Not clear from the string what these newly printed values are. Improve the string/description. > + reported, served, lbit_vec[0], priv->next_slave); > > if (mlx4_ARM_COMM_CHANNEL(dev)) > mlx4_warn(dev, "Failed to arm comm channel events\n"); > diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4.h b/drivers/net/ethernet/mellanox/mlx4/mlx4.h > index 64bed7ac3836..cd6ba80f4c90 100644 > --- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h > +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h > @@ -924,6 +924,7 @@ struct mlx4_priv { > > atomic_t opreq_count; > struct work_struct opreq_task; > + u32 next_slave; /* mlx4_master_comm_channel */ Move it to a more specific struct, consider struct mlx4_mfunc_master_ctx. > }; > > static inline struct mlx4_priv *mlx4_priv(struct mlx4_dev *dev) > Please submit to netdev mailing list, and CC needed maintainers.