From patchwork Tue Feb 10 10:33:48 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Michal Kazior X-Patchwork-Id: 438322 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id B6E6F140111 for ; Tue, 10 Feb 2015 21:34:01 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754594AbbBJKdw (ORCPT ); Tue, 10 Feb 2015 05:33:52 -0500 Received: from mail-we0-f170.google.com ([74.125.82.170]:45113 "EHLO mail-we0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753711AbbBJKdt convert rfc822-to-8bit (ORCPT ); Tue, 10 Feb 2015 05:33:49 -0500 Received: by mail-we0-f170.google.com with SMTP id q59so23827283wes.1 for ; Tue, 10 Feb 2015 02:33:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tieto.com; s=google; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=lV/dJ68n60PZ8MmsyPvFJOjZbZqEwYD0kD3UPlTEEMM=; b=LxforFNG15eJwCeT/zBxs2ngeZd99oLv2oglzEg+w7CUsNLzrolHtDXDXX+VpbaQL7 jLaUnL30yAGu2XK9bIDNYYiRkVGGgmZXo5Bt/uTJ8D+rLkN+eLrCYtapVCTs7XQZuB+D k1LcxiQLVIA+OVFDN5+nBJxyz8E1S9Axv8aA0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=lV/dJ68n60PZ8MmsyPvFJOjZbZqEwYD0kD3UPlTEEMM=; b=SaIBLzQX319rPaFnZj8NV2796EUMZrqFThCnx5bZSSG872/X9+v+iQcNomNjv3MQMO 62VLxovntRIOQjA6rZ9d0UUNCY5YRqrBrGMn7CNziW4vh2ghrPGPgCsFebQfl01PXPYm 4Jp0csSPPoBAbWlqeYCZHYDskWufRVKzNJ9l8sZrD8vp2HOlT03tF+C/2MHVcepLOzgN 3ExDeB47iORRRnnJn+RfsaupP4InPqKP49kMD+wp8m5OHvshtnW6Td2xzIaa5P+1i8pQ jkDcYeH0vHfgnLYmnkFIF5jKVHG4eEkUDbdn8cUri1c/D2lJ+AuPLo5n9nFWzpiL3UFC l89A== X-Gm-Message-State: ALoCoQkbli6Vx8oQGHhKKQO5/ScYlHkjFRz97C82zcUQgCRT0sme/Pft2u9U3aQnQhYHGTm0GRzabCvZKsQ9UD1wvdnpgGxvK1ia2Wlq/z/39xdGjBvuMv0= MIME-Version: 1.0 X-Received: by 10.180.74.141 with SMTP id t13mr44419655wiv.45.1423564428397; Tue, 10 Feb 2015 02:33:48 -0800 (PST) Received: by 10.27.101.138 with HTTP; Tue, 10 Feb 2015 02:33:48 -0800 (PST) In-Reply-To: <1423494690.31870.189.camel@edumazet-glaptop2.roam.corp.google.com> References: <1422537297.21689.15.camel@edumazet-glaptop2.roam.corp.google.com> <1422628835.21689.95.camel@edumazet-glaptop2.roam.corp.google.com> <1422903136.21689.114.camel@edumazet-glaptop2.roam.corp.google.com> <1422926330.21689.138.camel@edumazet-glaptop2.roam.corp.google.com> <1422973660.907.10.camel@edumazet-glaptop2.roam.corp.google.com> <1423051045.907.108.camel@edumazet-glaptop2.roam.corp.google.com> <1423053531.907.115.camel@edumazet-glaptop2.roam.corp.google.com> <1423055810.907.125.camel@edumazet-glaptop2.roam.corp.google.com> <1423056591.907.130.camel@edumazet-glaptop2.roam.corp.google.com> <1423084303.31870.15.camel@edumazet-glaptop2.roam.corp.google.com> <1423141038.31870.38.camel@edumazet-glaptop2.roam.corp.google.com> <1423142342.31870.49.camel@edumazet-glaptop2.roam.corp.google.com> <1423147286.31870.59.camel@edumazet-glaptop2.roam.corp.google.com> <1423156205.31870.86.camel@edumazet-glaptop2.roam.corp.google.com> <1423230001.31870.128.camel@edumazet-glaptop2.roam.corp.google.com> <1423230785.31870.131.camel@edumazet-glaptop2.roam.corp.google.com> <1423494690.31870.189.camel@edumazet-glaptop2.roam.corp.google.com> Date: Tue, 10 Feb 2015 11:33:48 +0100 Message-ID: Subject: Re: Throughput regression with `tcp: refine TSO autosizing` From: Michal Kazior To: Eric Dumazet Cc: Neal Cardwell , linux-wireless , Network Development , Eyal Perry X-DomainID: tieto.com Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 9 February 2015 at 16:11, Eric Dumazet wrote: > On Mon, 2015-02-09 at 14:47 +0100, Michal Kazior wrote: [...] > This is not what I suggested. > > If you test this on any other network device, you'll have > sk->sk_tx_completion_delay_us == 0 > > amount = 0 * (sk->sk_pacing_rate >> 10); --> 0 > limit = max(2 * skb->truesize, amount >> 10); --> 2 * skb->truesize You're right. Sorry for mixing up. > So non TSO/GSO NIC will not be able to queue more than 2 MSS (one MSS > per skb) > > Then if you store only the last tx completion, you have the possibility > of having a last packet of a train (say a retransmit) to make it very > low. > > Ideally the formula would be in TCP something very fast to compute : > > amount = (sk->sk_pacing_rate >> 10) + sk->tx_completion_delay_cushion; > limit = max(2 * skb->truesize, amount); > limit = min_t(u32, limit, sysctl_tcp_limit_output_bytes); > > So a 'problematic' driver would have to do the math (64 bit maths) like > this : > > > sk->tx_completion_delay_cushion = ewma_tx_delay * sk->sk_pacing_rate; Hmm. So I've done like you suggested (hopefully I didn't mix anything up this time around). I now get pre-regression performance, ~250mbps on 1 flow, 600mbps on 5 flows (vs 250mbps whatever number of flows). Michał BUG_ON(!tso_segs); @@ -2053,7 +2054,9 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, * of queued bytes to ensure line rate. * One example is wifi aggregation (802.11 AMPDU) */ - limit = max(2 * skb->truesize, sk->sk_pacing_rate >> 10); + amount = (sk->sk_pacing_rate >> 10) + + sk->sk_tx_completion_delay_cushion; + limit = max(2 * skb->truesize, amount); limit = min_t(u32, limit, sysctl_tcp_limit_output_bytes); if (atomic_read(&sk->sk_wmem_alloc) > limit) { --- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c index 367e896..a29111c 100644 --- a/drivers/net/wireless/ath/ath10k/core.c +++ b/drivers/net/wireless/ath/ath10k/core.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "core.h" #include "mac.h" @@ -1423,6 +1424,7 @@ struct ath10k *ath10k_core_create(size_t priv_size, struct device *dev, init_dummy_netdev(&ar->napi_dev); ieee80211_napi_add(ar->hw, &ar->napi, &ar->napi_dev, ath10k_core_napi_dummy_poll, 64); + ewma_init(&ar->tx_delay_us, 16384, 8); ret = ath10k_debug_create(ar); if (ret) diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h index 3be3a59..34f6d78 100644 --- a/drivers/net/wireless/ath/ath10k/core.h +++ b/drivers/net/wireless/ath/ath10k/core.h @@ -24,6 +24,7 @@ #include #include #include +#include #include "htt.h" #include "htc.h" @@ -82,6 +83,7 @@ struct ath10k_skb_cb { dma_addr_t paddr; u8 eid; u8 vdev_id; + ktime_t stamp; struct { u8 tid; @@ -625,6 +627,7 @@ struct ath10k { struct net_device napi_dev; struct napi_struct napi; + struct ewma tx_delay_us; #ifdef CONFIG_ATH10K_DEBUGFS struct ath10k_debug debug; diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index 15e47f4..5efb2a7 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -2620,6 +2620,7 @@ static void ath10k_tx(struct ieee80211_hw *hw, if (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE) ath10k_dbg(ar, ATH10K_DBG_MAC, "IEEE80211_TX_CTL_NO_CCK_RATE\n"); + ATH10K_SKB_CB(skb)->stamp = ktime_get(); ATH10K_SKB_CB(skb)->htt.is_offchan = false; ATH10K_SKB_CB(skb)->htt.tid = ath10k_tx_h_get_tid(hdr); ATH10K_SKB_CB(skb)->vdev_id = ath10k_tx_h_get_vdev_id(ar, vif); diff --git a/drivers/net/wireless/ath/ath10k/txrx.c b/drivers/net/wireless/ath/ath10k/txrx.c index 3f00cec..0f5f0f2 100644 --- a/drivers/net/wireless/ath/ath10k/txrx.c +++ b/drivers/net/wireless/ath/ath10k/txrx.c @@ -15,6 +15,8 @@ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ +#include +#include #include "core.h" #include "txrx.h" #include "htt.h" @@ -82,6 +84,16 @@ void ath10k_txrx_tx_unref(struct ath10k_htt *htt, ath10k_report_offchan_tx(htt->ar, msdu); + if (msdu->sk) { + ewma_add(&ar->tx_delay_us, + ktime_to_ns(ktime_sub(ktime_get(), skb_cb->stamp)) / + NSEC_PER_USEC); + + ACCESS_ONCE(msdu->sk->sk_tx_completion_delay_cushion) = + (ewma_read(&ar->tx_delay_us) * + msdu->sk->sk_pacing_rate) >> 20; + } + info = IEEE80211_SKB_CB(msdu); memset(&info->status, 0, sizeof(info->status)); trace_ath10k_txrx_tx_unref(ar, tx_done->msdu_id); diff --git a/include/net/sock.h b/include/net/sock.h index 2210fec..6772543 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -391,6 +391,7 @@ struct sock { gfp_t sk_allocation; u32 sk_pacing_rate; /* bytes per second */ u32 sk_max_pacing_rate; + u32 sk_tx_completion_delay_cushion; netdev_features_t sk_route_caps; netdev_features_t sk_route_nocaps; int sk_gso_type; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 65caf8b..526a568 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1996,6 +1996,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, max_segs = tcp_tso_autosize(sk, mss_now); while ((skb = tcp_send_head(sk))) { unsigned int limit; + unsigned int amount; tso_segs = tcp_init_tso_segs(sk, skb, mss_now);