From: Jose Abreu <Jose.Abreu@synopsys.com>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
Jose Abreu <Jose.Abreu@synopsys.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
Joao Pinto <Joao.Pinto@synopsys.com>,
"David S . Miller" <davem@davemloft.net>,
Giuseppe Cavallaro <peppe.cavallaro@st.com>,
Alexandre Torgue <alexandre.torgue@st.com>
Subject: RE: [PATCH net-next v2 06/10] net: stmmac: Do not disable interrupts when cleaning TX
Date: Mon, 1 Jul 2019 10:15:17 +0000 [thread overview]
Message-ID: <BN8PR12MB326638B0BA74DA762C89DF54D3F90@BN8PR12MB3266.namprd12.prod.outlook.com> (raw)
In-Reply-To: <CA+FuTSc4MFfjBNpvN2hRh9_MRmxSYw2xY6wp32Hsbw0E=pqUdw@mail.gmail.com>
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
> By the
>
> if ((status & handle_rx) && (chan < priv->plat->rx_queues_to_use)) {
> stmmac_disable_dma_irq(priv, priv->ioaddr, chan);
> napi_schedule_irqoff(&ch->rx_napi);
> }
>
> branch directly above? If so, is it possible to have fewer rx than tx
> queues and miss this?
Yes, it is possible.
> this logic seems more complex than needed?
>
> if (status)
> status |= handle_rx | handle_tx;
>
> if ((status & handle_rx) && (chan < priv->plat->rx_queues_to_use)) {
>
> }
>
> if ((status & handle_tx) && (chan < priv->plat->tx_queues_to_use)) {
>
> }
>
> status & handle_rx implies status & handle_tx and vice versa.
This is removed in patch 09/10.
> > - if (work_done < budget && napi_complete_done(napi, work_done))
> > - stmmac_enable_dma_irq(priv, priv->ioaddr, chan);
> > + if (work_done < budget)
> > + napi_complete_done(napi, work_done);
>
> It does seem odd that stmmac_napi_poll_rx and stmmac_napi_poll_tx both
> call stmmac_enable_dma_irq(..) independent of the other. Shouldn't the
> IRQ remain masked while either is active or scheduled? That is almost
> what this patch does, though not exactly.
After patch 09/10 the interrupts will only be disabled by RX NAPI and
re-enabled by it again. I can do some tests on whether disabling
interrupts independently gives more performance but I wouldn't expect so
because the real bottleneck when I do iperf3 tests is the RX path ...
next prev parent reply other threads:[~2019-07-01 10:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-28 7:29 [PATCH net-next v2 00/10] net: stmmac: 10GbE using XGMAC Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 01/10] net: stmmac: dwxgmac: Enable EDMA by default Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 02/10] net: stmmac: Do not try to enable PHY EEE if MAC does not support it Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 03/10] net: stmmac: Decrease default RX Watchdog value Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 04/10] net: stmmac: dwxgmac: Fix the undefined burst setting Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 05/10] net: stmmac: Add the missing speeds that XGMAC supports Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 06/10] net: stmmac: Do not disable interrupts when cleaning TX Jose Abreu
2019-06-28 19:08 ` Willem de Bruijn
2019-07-01 10:15 ` Jose Abreu [this message]
2019-07-01 12:23 ` Willem de Bruijn
2019-06-28 7:29 ` [PATCH net-next v2 07/10] net: stmmac: Enable support for > 32 Bits addressing in XGMAC Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 08/10] net: stmmac: Update RX Tail Pointer to last free entry Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 09/10] net: stmmac: Only disable interrupts if NAPI is scheduled Jose Abreu
2019-06-28 7:29 ` [PATCH net-next v2 10/10] net: stmmac: Update Kconfig entry Jose Abreu
2019-06-28 16:24 ` [PATCH net-next v2 00/10] net: stmmac: 10GbE using XGMAC David Miller
2019-07-01 10:19 ` Jose Abreu
2019-07-01 17:46 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BN8PR12MB326638B0BA74DA762C89DF54D3F90@BN8PR12MB3266.namprd12.prod.outlook.com \
--to=jose.abreu@synopsys.com \
--cc=Joao.Pinto@synopsys.com \
--cc=alexandre.torgue@st.com \
--cc=davem@davemloft.net \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=peppe.cavallaro@st.com \
--cc=willemdebruijn.kernel@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).