From patchwork Wed Mar 13 12:54:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Vecera X-Patchwork-Id: 13591379 X-Patchwork-Delegate: kuba@kernel.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 705A743AAF for ; Wed, 13 Mar 2024 12:55:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710334509; cv=none; b=u3hu+s5MSmRdrTE0ZmarmXY4nBV1XzFfYyUeURjG+hYpAA2/N5DFWNfGopDBqWR+R+b1CuRQSlwznWypTsbFnmKqj1QI/R8eygy4q3lIpL8d5We2CWfj2E/2b4gPMryuC5MoH/hS1xbCv7764EV6NE92WL8mo/WXEwVboxfvyXE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710334509; c=relaxed/simple; bh=sh7lOn799mdRNo9SNh2T7fssV2zC50KXVdJoi0KTXRE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=prsd12jUMyaFCsrx0oNT5c7ARPBkUI5ISMOprrdqgfwkmCtHbgSgbmUUT3kUHJM1y2vKfakYJAHORox2kmGfQRIN7T6Wd4ybt1qUIgefm+zC1G1fUVaQaDupmUyOi0i30DTylg/6/gpeWR2kZ9lEMwdslcG07rtdxu4CXCfy198= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=a++qMQSq; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="a++qMQSq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710334506; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=h/UYi6EhK4kWHCiuuewAtpIQWiza2uvSvfzWNm0vBG0=; b=a++qMQSqiGHWV3kjZDFLfflUvxeQo3RfGd8sSBz+oGrTnDV0jFMO1w6ecYx/uDOAJQCB2o JzGg9DC1V7byHbrJNkdaMaarlO81fcg1UqcJyEFgnSgC8SFWl6DtqJ49lXj+m2XLCohGrn EZ5oF9ubF7AORwnvL2ziPcm9IAWnDc0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-615-N9sYoLSWOzi0ey4wgDZ8yA-1; Wed, 13 Mar 2024 08:55:00 -0400 X-MC-Unique: N9sYoLSWOzi0ey4wgDZ8yA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 33595101A56C; Wed, 13 Mar 2024 12:55:00 +0000 (UTC) Received: from p1.luc.cera.cz (unknown [10.45.224.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id 074503C22; Wed, 13 Mar 2024 12:54:57 +0000 (UTC) From: Ivan Vecera To: netdev@vger.kernel.org Cc: pawel.chmielewski@intel.com, aleksandr.loktionov@intel.com, mschmidt@redhat.com, Hugo Ferreira , Jesse Brandeburg , Tony Nguyen , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , intel-wired-lan@lists.osuosl.org (moderated list:INTEL ETHERNET DRIVERS), linux-kernel@vger.kernel.org (open list) Subject: [PATCH net] i40e: Enforce software interrupt during busy-poll exit Date: Wed, 13 Mar 2024 13:54:56 +0100 Message-ID: <20240313125457.19475-1-ivecera@redhat.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 X-Patchwork-Delegate: kuba@kernel.org As for ice bug fixed by commit b7306b42beaf ("ice: manage interrupts during poll exit") I'm seeing the similar issue also with i40e driver. In certain situation when busy-loop is enabled together with adaptive coalescing, the driver occasionally miss that there are outstanding descriptors to clean when exiting busy poll. Try to catch the remaining work by triggering a software interrupt when exiting busy poll. No extra interrupts will be generated when busy polling is not used. The issue was found when running sockperf ping-pong tcp test with adaptive coalescing and busy poll enabled (50 as value busy_pool and busy_read sysctl knobs) and results in huge latency spikes with more than 100000us. The fix is inspired from the ice driver and do the following: 1) During napi poll exit in case of busy-poll (napo_complete_done() returns false) this is recorded to q_vector that we were in busy loop. 2) In i40e_update_enable_itr() - updates refreshed ITR intervals directly using PFINT_ITRN register - if we are exiting ordinary poll then just enables the interrupt using PFINT_DYN_CTLN - if we are exiting busy poll then enables the interrupt and additionally triggers an immediate software interrupt to catch any pending clean-ups 3) Reuses unused 3rd ITR (interrupt throttle) index and set it to 20K interrupts per second to limit the number of these sw interrupts. Test results ============ Prior: [root@dell-per640-07 net]# sockperf ping-pong -i 10.9.9.1 --tcp -m 1000 --mps=max -t 120 sockperf: == version #3.10-no.git == sockperf[CLIENT] send on:sockperf: using recvfrom() to block on socket(s) [ 0] IP = 10.9.9.1 PORT = 11111 # TCP sockperf: Warmup stage (sending a few dummy messages)... sockperf: Starting test... sockperf: Test end (interrupted by timer) sockperf: Test ended sockperf: [Total Run] RunTime=119.999 sec; Warm up time=400 msec; SentMessages=2438563; ReceivedMessages=2438562 sockperf: ========= Printing statistics for Server No: 0 sockperf: [Valid Duration] RunTime=119.549 sec; SentMessages=2429473; ReceivedMessages=2429473 sockperf: ====> avg-latency=24.571 (std-dev=93.297, mean-ad=4.904, median-ad=1.510, siqr=1.063, cv=3.797, std-error=0.060, 99.0% ci=[24.417, 24.725]) sockperf: # dropped messages = 0; # duplicated messages = 0; # out-of-order messages = 0 sockperf: Summary: Latency is 24.571 usec sockperf: Total 2429473 observations; each percentile contains 24294.73 observations sockperf: ---> observation = 103294.331 sockperf: ---> percentile 99.999 = 45.633 sockperf: ---> percentile 99.990 = 37.013 sockperf: ---> percentile 99.900 = 35.910 sockperf: ---> percentile 99.000 = 33.390 sockperf: ---> percentile 90.000 = 28.626 sockperf: ---> percentile 75.000 = 27.741 sockperf: ---> percentile 50.000 = 26.743 sockperf: ---> percentile 25.000 = 25.614 sockperf: ---> observation = 12.220 After: [root@dell-per640-07 net]# sockperf ping-pong -i 10.9.9.1 --tcp -m 1000 --mps=max -t 120 sockperf: == version #3.10-no.git == sockperf[CLIENT] send on:sockperf: using recvfrom() to block on socket(s) [ 0] IP = 10.9.9.1 PORT = 11111 # TCP sockperf: Warmup stage (sending a few dummy messages)... sockperf: Starting test... sockperf: Test end (interrupted by timer) sockperf: Test ended sockperf: [Total Run] RunTime=119.999 sec; Warm up time=400 msec; SentMessages=2400055; ReceivedMessages=2400054 sockperf: ========= Printing statistics for Server No: 0 sockperf: [Valid Duration] RunTime=119.549 sec; SentMessages=2391186; ReceivedMessages=2391186 sockperf: ====> avg-latency=24.965 (std-dev=5.934, mean-ad=4.642, median-ad=1.485, siqr=1.067, cv=0.238, std-error=0.004, 99.0% ci=[24.955, 24.975]) sockperf: # dropped messages = 0; # duplicated messages = 0; # out-of-order messages = 0 sockperf: Summary: Latency is 24.965 usec sockperf: Total 2391186 observations; each percentile contains 23911.86 observations sockperf: ---> observation = 195.841 sockperf: ---> percentile 99.999 = 45.026 sockperf: ---> percentile 99.990 = 39.009 sockperf: ---> percentile 99.900 = 35.922 sockperf: ---> percentile 99.000 = 33.482 sockperf: ---> percentile 90.000 = 28.902 sockperf: ---> percentile 75.000 = 27.821 sockperf: ---> percentile 50.000 = 26.860 sockperf: ---> percentile 25.000 = 25.685 sockperf: ---> observation = 12.277 Reported-by: Hugo Ferreira Signed-off-by: Ivan Vecera --- drivers/net/ethernet/intel/i40e/i40e.h | 1 + drivers/net/ethernet/intel/i40e/i40e_main.c | 6 +++ .../net/ethernet/intel/i40e/i40e_register.h | 2 + drivers/net/ethernet/intel/i40e/i40e_txrx.c | 46 ++++++++++++++----- drivers/net/ethernet/intel/i40e/i40e_txrx.h | 1 + 5 files changed, 45 insertions(+), 11 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h index 9b701615c7c6..4d2b05de6c63 100644 --- a/drivers/net/ethernet/intel/i40e/i40e.h +++ b/drivers/net/ethernet/intel/i40e/i40e.h @@ -908,6 +908,7 @@ struct i40e_q_vector { struct rcu_head rcu; /* to avoid race with update stats on free */ char name[I40E_INT_NAME_STR_LEN]; bool arm_wb_state; + bool in_busy_poll; int irq_num; /* IRQ assigned to this q_vector */ } ____cacheline_internodealigned_in_smp; diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 89a3401d20ab..1ea6d06b0acc 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -3915,6 +3915,12 @@ static void i40e_vsi_configure_msix(struct i40e_vsi *vsi) q_vector->tx.target_itr >> 1); q_vector->tx.current_itr = q_vector->tx.target_itr; + /* Set ITR for software interrupts triggered after exiting + * busy-loop polling. + */ + wr32(hw, I40E_PFINT_ITRN(I40E_SW_ITR, vector - 1), + I40E_ITR_20K); + wr32(hw, I40E_PFINT_RATEN(vector - 1), i40e_intrl_usec_to_reg(vsi->int_rate_limit)); diff --git a/drivers/net/ethernet/intel/i40e/i40e_register.h b/drivers/net/ethernet/intel/i40e/i40e_register.h index 14ab642cafdb..baa6bb68bcf8 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_register.h +++ b/drivers/net/ethernet/intel/i40e/i40e_register.h @@ -335,6 +335,8 @@ #define I40E_PFINT_DYN_CTLN_INTERVAL_SHIFT 5 #define I40E_PFINT_DYN_CTLN_SW_ITR_INDX_ENA_SHIFT 24 #define I40E_PFINT_DYN_CTLN_SW_ITR_INDX_ENA_MASK I40E_MASK(0x1, I40E_PFINT_DYN_CTLN_SW_ITR_INDX_ENA_SHIFT) +#define I40E_PFINT_DYN_CTLN_SW_ITR_INDX_SHIFT 25 +#define I40E_PFINT_DYN_CTLN_SW_ITR_INDX_MASK I40E_MASK(0x3, I40E_PFINT_DYN_CTLN_SW_ITR_INDX_SHIFT) #define I40E_PFINT_ICR0 0x00038780 /* Reset: CORER */ #define I40E_PFINT_ICR0_INTEVENT_SHIFT 0 #define I40E_PFINT_ICR0_INTEVENT_MASK I40E_MASK(0x1, I40E_PFINT_ICR0_INTEVENT_SHIFT) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 0d7177083708..356c3140adf3 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -2658,8 +2658,22 @@ static inline u32 i40e_buildreg_itr(const int type, u16 itr) return val; } -/* a small macro to shorten up some long lines */ -#define INTREG I40E_PFINT_DYN_CTLN +static inline u32 i40e_buildreg_swint(int type) +{ + u32 val; + + /* 1. Enable the interrupt + * 2. Do not modify any ITR interval + * 3. Trigger a SW interrupt specified by type + */ + val = I40E_PFINT_DYN_CTLN_INTENA_MASK | + I40E_PFINT_DYN_CTLN_ITR_INDX_MASK | /* set noitr */ + I40E_PFINT_DYN_CTLN_SWINT_TRIG_MASK | + I40E_PFINT_DYN_CTLN_SW_ITR_INDX_ENA_MASK | + FIELD_PREP(I40E_PFINT_DYN_CTLN_SW_ITR_INDX_MASK, type); + + return val; +} /* The act of updating the ITR will cause it to immediately trigger. In order * to prevent this from throwing off adaptive update statistics we defer the @@ -2702,8 +2716,8 @@ static inline void i40e_update_enable_itr(struct i40e_vsi *vsi, */ if (q_vector->rx.target_itr < q_vector->rx.current_itr) { /* Rx ITR needs to be reduced, this is highest priority */ - intval = i40e_buildreg_itr(I40E_RX_ITR, - q_vector->rx.target_itr); + wr32(hw, I40E_PFINT_ITRN(I40E_RX_ITR, q_vector->reg_idx), + q_vector->rx.target_itr >> 1); q_vector->rx.current_itr = q_vector->rx.target_itr; q_vector->itr_countdown = ITR_COUNTDOWN_START; } else if ((q_vector->tx.target_itr < q_vector->tx.current_itr) || @@ -2712,25 +2726,33 @@ static inline void i40e_update_enable_itr(struct i40e_vsi *vsi, /* Tx ITR needs to be reduced, this is second priority * Tx ITR needs to be increased more than Rx, fourth priority */ - intval = i40e_buildreg_itr(I40E_TX_ITR, - q_vector->tx.target_itr); + wr32(hw, I40E_PFINT_ITRN(I40E_TX_ITR, q_vector->reg_idx), + q_vector->tx.target_itr >> 1); q_vector->tx.current_itr = q_vector->tx.target_itr; q_vector->itr_countdown = ITR_COUNTDOWN_START; } else if (q_vector->rx.current_itr != q_vector->rx.target_itr) { /* Rx ITR needs to be increased, third priority */ - intval = i40e_buildreg_itr(I40E_RX_ITR, - q_vector->rx.target_itr); + wr32(hw, I40E_PFINT_ITRN(I40E_RX_ITR, q_vector->reg_idx), + q_vector->rx.target_itr >> 1); q_vector->rx.current_itr = q_vector->rx.target_itr; q_vector->itr_countdown = ITR_COUNTDOWN_START; } else { /* No ITR update, lowest priority */ - intval = i40e_buildreg_itr(I40E_ITR_NONE, 0); if (q_vector->itr_countdown) q_vector->itr_countdown--; } - if (!test_bit(__I40E_VSI_DOWN, vsi->state)) - wr32(hw, INTREG(q_vector->reg_idx), intval); + /* Do not enable interrupt if VSI is down */ + if (test_bit(__I40E_VSI_DOWN, vsi->state)) + return; + + if (!q_vector->in_busy_poll) { + intval = i40e_buildreg_itr(I40E_ITR_NONE, 0); + } else { + q_vector->in_busy_poll = false; + intval = i40e_buildreg_swint(I40E_SW_ITR); + } + wr32(hw, I40E_PFINT_DYN_CTLN(q_vector->reg_idx), intval); } /** @@ -2845,6 +2867,8 @@ int i40e_napi_poll(struct napi_struct *napi, int budget) */ if (likely(napi_complete_done(napi, work_done))) i40e_update_enable_itr(vsi, q_vector); + else + q_vector->in_busy_poll = true; return min(work_done, budget - 1); } diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h index abf15067eb5d..2cdc7de6301c 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h @@ -68,6 +68,7 @@ enum i40e_dyn_idx { /* these are indexes into ITRN registers */ #define I40E_RX_ITR I40E_IDX_ITR0 #define I40E_TX_ITR I40E_IDX_ITR1 +#define I40E_SW_ITR I40E_IDX_ITR2 /* Supported RSS offloads */ #define I40E_DEFAULT_RSS_HENA ( \