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=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 E8D3CC4363D for ; Fri, 25 Sep 2020 12:09:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7767321D7A for ; Fri, 25 Sep 2020 12:09:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jVeVlrKc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728313AbgIYMJh (ORCPT ); Fri, 25 Sep 2020 08:09:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43496 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728038AbgIYMJh (ORCPT ); Fri, 25 Sep 2020 08:09:37 -0400 Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601035775; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vKv79pKABb3lcxxJJ/iKHHf7+5qMSzzl2wR9bWa0VUs=; b=jVeVlrKcjbgU74cV2EQGKK7ieK6RaBgMN2rE+TKlawY3DjMw7bJOukNQduzp0l8OnQvu4k MDlU7wvboZKeoM5cUgp8L6DOsAWTrXTQxblJ/0VORj9Ahfe0/igH8ZPJzHZCgDowlD0KIK gJ6FGHqu26dSISjsMREk2MJZHhUtiAw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-281-h9lD5ihNPDe_MeBfT7J50A-1; Fri, 25 Sep 2020 08:09:33 -0400 X-MC-Unique: h9lD5ihNPDe_MeBfT7J50A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2A4B58030CD; Fri, 25 Sep 2020 12:09:32 +0000 (UTC) Received: from carbon (unknown [10.36.110.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8FC4555761; Fri, 25 Sep 2020 12:09:22 +0000 (UTC) Date: Fri, 25 Sep 2020 14:09:20 +0200 From: Jesper Dangaard Brouer To: Lorenzo Bianconi Cc: Lorenzo Bianconi , Network Development , "David S. Miller" , Jakub Kicinski , Eelco Chaudron , thomas.petazzoni@bootlin.com, brouer@redhat.com Subject: Re: [PATCH net-next] net: mvneta: try to use in-irq pp cache in mvneta_txq_bufs_free Message-ID: <20200925140920.47bec9cf@carbon> In-Reply-To: References: <4f6602e98fdaef1610e948acec19a5de51fb136e.1601027617.git.lorenzo@kernel.org> <20200925125213.4981cff8@carbon> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 25 Sep 2020 13:29:00 +0200 Lorenzo Bianconi wrote: > > > > On Fri, 25 Sep 2020 12:01:32 +0200 > > Lorenzo Bianconi wrote: > > > > > Try to recycle the xdp tx buffer into the in-irq page_pool cache if > > > mvneta_txq_bufs_free is executed in the NAPI context. > > > > NACK - I don't think this is safe. That is also why I named the > > function postfix rx_napi. The page pool->alloc.cache is associated > > with the drivers RX-queue. The xdp_frame's that gets freed could be > > coming from a remote driver that use page_pool. This remote drivers > > RX-queue processing can run concurrently on a different CPU, than this > > drivers TXQ-cleanup. > > ack, right. What about if we do it just XDP_TX use case? Like: > > if (napi && buf->type == MVNETA_TYPE_XDP_TX) > xdp_return_frame_rx_napi(buf->xdpf); > else > xdp_return_frame(buf->xdpf); > > In this way we are sure the packet is coming from local page_pool. Yes, that case XDP_TX should be safe. > > > > If you want to speedup this, I instead suggest that you add a > > xdp_return_frame_bulk API. > > I will look at it Great! Notice that bulk return should be easy/obvious in most drivers, as they (like mvneta in mvneta_txq_bufs_free()) have a loop that process several TXQ completions. I did a quick tests on mlx5 with xdp_redirect_map and perf report shows __xdp_return calls at the top#1 overhead. # Overhead CPU Symbol # ........ ... .................................... # 8.46% 003 [k] __xdp_return 6.41% 003 [k] dma_direct_map_page 4.65% 003 [k] bpf_xdp_redirect_map 4.58% 003 [k] dma_direct_unmap_page 4.04% 003 [k] xdp_do_redirect 3.53% 003 [k] __page_pool_put_page 3.27% 003 [k] dma_direct_sync_single_for_cpu 2.63% 003 [k] dev_map_enqueue 2.28% 003 [k] page_pool_refill_alloc_cache 1.69% 003 [k] bq_enqueue.isra.0 1.15% 003 [k] _raw_spin_lock 0.92% 003 [k] xdp_return_frame Thus, there will be a benefit from implementing a bulk return. Also for your XDP_TX case, as the overhead in __xdp_return also exist for rx_napi variant. > > > Signed-off-by: Lorenzo Bianconi > > > --- > > > drivers/net/ethernet/marvell/mvneta.c | 11 +++++++---- > > > 1 file changed, 7 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c > > > index 14df3aec285d..646fbf4ed638 100644 > > > --- a/drivers/net/ethernet/marvell/mvneta.c > > > +++ b/drivers/net/ethernet/marvell/mvneta.c > > > @@ -1831,7 +1831,7 @@ static struct mvneta_tx_queue *mvneta_tx_done_policy(struct mvneta_port *pp, > > > /* Free tx queue skbuffs */ > > > static void mvneta_txq_bufs_free(struct mvneta_port *pp, > > > struct mvneta_tx_queue *txq, int num, > > > - struct netdev_queue *nq) > > > + struct netdev_queue *nq, bool napi) > > > { > > > unsigned int bytes_compl = 0, pkts_compl = 0; > > > int i; > > > @@ -1854,7 +1854,10 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp, > > > dev_kfree_skb_any(buf->skb); > > > } else if (buf->type == MVNETA_TYPE_XDP_TX || > > > buf->type == MVNETA_TYPE_XDP_NDO) { > > > - xdp_return_frame(buf->xdpf); > > > + if (napi) > > > + xdp_return_frame_rx_napi(buf->xdpf); > > > + else > > > + xdp_return_frame(buf->xdpf); > > > } > > > } > > > > > > @@ -1872,7 +1875,7 @@ static void mvneta_txq_done(struct mvneta_port *pp, > > > if (!tx_done) > > > return; > > > > > > - mvneta_txq_bufs_free(pp, txq, tx_done, nq); > > > + mvneta_txq_bufs_free(pp, txq, tx_done, nq, true); > > > > > > txq->count -= tx_done; > > > > > > @@ -2859,7 +2862,7 @@ static void mvneta_txq_done_force(struct mvneta_port *pp, > > > struct netdev_queue *nq = netdev_get_tx_queue(pp->dev, txq->id); > > > int tx_done = txq->count; > > > > > > - mvneta_txq_bufs_free(pp, txq, tx_done, nq); > > > + mvneta_txq_bufs_free(pp, txq, tx_done, nq, false); > > > > > > /* reset txq */ > > > txq->count = 0; -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer