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Message-ID: <CAHrpEqQkuH1JQfKFa=S+ZqbnHpR_SdihM3_dJ++nokV1tczM_Q@mail.gmail.com>
Date: Wed, 2 Mar 2016 10:47:19 -0600
From: Zhi Li <lznuaa@...il.com>
To: Troy Kisky <troy.kisky@...ndarydevices.com>
Cc: Fugang Duan <fugang.duan@....com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"davem@...emloft.net" <davem@...emloft.net>,
"b38611@...escale.com" <b38611@...escale.com>,
"fabio.estevam@...escale.com" <fabio.estevam@...escale.com>,
"l.stach@...gutronix.de" <l.stach@...gutronix.de>,
"andrew@...n.ch" <andrew@...n.ch>,
"tremyfr@...il.com" <tremyfr@...il.com>,
"linux@....linux.org.uk" <linux@....linux.org.uk>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"laci@...ndarydevices.com" <laci@...ndarydevices.com>,
"shawnguo@...nel.org" <shawnguo@...nel.org>,
"johannes@...solutions.net" <johannes@...solutions.net>,
"stillcompiling@...il.com" <stillcompiling@...il.com>,
"sergei.shtylyov@...entembedded.com"
<sergei.shtylyov@...entembedded.com>,
"arnd@...db.de" <arnd@...db.de>
Subject: Re: [PATCH net-next V2 04/16] net: fec: reduce interrupts
On Wed, Mar 2, 2016 at 10:12 AM, Troy Kisky
<troy.kisky@...ndarydevices.com> wrote:
> On 3/2/2016 8:13 AM, Fugang Duan wrote:
>> From: Troy Kisky <troy.kisky@...ndarydevices.com> Sent: Thursday, February 25, 2016 8:37 AM
>>> To: netdev@...r.kernel.org; davem@...emloft.net; b38611@...escale.com
>>> Cc: fabio.estevam@...escale.com; l.stach@...gutronix.de; andrew@...n.ch;
>>> tremyfr@...il.com; linux@....linux.org.uk; linux-arm-
>>> kernel@...ts.infradead.org; laci@...ndarydevices.com; shawnguo@...nel.org;
>>> johannes@...solutions.net; stillcompiling@...il.com;
>>> sergei.shtylyov@...entembedded.com; arnd@...db.de; Troy Kisky
>>> <troy.kisky@...ndarydevices.com>
>>> Subject: [PATCH net-next V2 04/16] net: fec: reduce interrupts
>>>
>>> By clearing the NAPI interrupts in the NAPI routine and not in the interrupt
>>> handler, we can reduce the number of interrupts. We also don't need any
>>> status variables as the registers are still valid.
>>>
>>> Also, notice that if budget pkts are received, the next call to fec_enet_rx_napi
>>> will now continue to receive the previously pending packets.
>>>
>>> Signed-off-by: Troy Kisky <troy.kisky@...ndarydevices.com>
>>> ---
>>> drivers/net/ethernet/freescale/fec.h | 6 +-
>>> drivers/net/ethernet/freescale/fec_main.c | 127 ++++++++++++----------------
>>> --
>>> 2 files changed, 50 insertions(+), 83 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/freescale/fec.h
>>> b/drivers/net/ethernet/freescale/fec.h
>>> index 195122e..001200b 100644
>>> --- a/drivers/net/ethernet/freescale/fec.h
>>> +++ b/drivers/net/ethernet/freescale/fec.h
>>> @@ -505,11 +505,7 @@ struct fec_enet_private {
>>>
>>> unsigned int total_tx_ring_size;
>>> unsigned int total_rx_ring_size;
>>> -
>>> - unsigned long work_tx;
>>> - unsigned long work_rx;
>>> - unsigned long work_ts;
>>> - unsigned long work_mdio;
>>> + uint events;
>>>
>>> struct platform_device *pdev;
>>>
>>> diff --git a/drivers/net/ethernet/freescale/fec_main.c
>>> b/drivers/net/ethernet/freescale/fec_main.c
>>> index c517194..4a218b9 100644
>>> --- a/drivers/net/ethernet/freescale/fec_main.c
>>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>>> @@ -70,8 +70,6 @@ static void fec_enet_itr_coal_init(struct net_device
>>> *ndev);
>>>
>>> #define DRIVER_NAME "fec"
>>>
>>> -#define FEC_ENET_GET_QUQUE(_x) ((_x == 0) ? 1 : ((_x == 1) ? 2 : 0))
>>> -
>>> /* Pause frame feild and FIFO threshold */
>>> #define FEC_ENET_FCE (1 << 5)
>>> #define FEC_ENET_RSEM_V 0x84
>>> @@ -1257,21 +1255,6 @@ static void fec_txq(struct net_device *ndev, struct
>>> fec_enet_private *fep,
>>> writel(0, txq->bd.reg_desc_active);
>>> }
>>>
>>> -static void
>>> -fec_enet_tx(struct net_device *ndev)
>>> -{
>>> - struct fec_enet_private *fep = netdev_priv(ndev);
>>> - struct fec_enet_priv_tx_q *txq;
>>> - u16 queue_id;
>>> - /* First process class A queue, then Class B and Best Effort queue */
>>> - for_each_set_bit(queue_id, &fep->work_tx, FEC_ENET_MAX_TX_QS)
>>> {
>>> - clear_bit(queue_id, &fep->work_tx);
>>> - txq = fep->tx_queue[FEC_ENET_GET_QUQUE(queue_id)];
>>> - fec_txq(ndev, fep, txq);
>>> - }
>>> - return;
>>> -}
>>> -
>>> static int
>>> fec_enet_new_rxbdp(struct net_device *ndev, struct bufdesc *bdp, struct
>>> sk_buff *skb) { @@ -1504,92 +1487,80 @@ rx_processing_done:
>>> return pkt_received;
>>> }
>>>
>>> -static int
>>> -fec_enet_rx(struct net_device *ndev, int budget) -{
>>> - int pkt_received = 0;
>>> - u16 queue_id;
>>> - struct fec_enet_private *fep = netdev_priv(ndev);
>>> - struct fec_enet_priv_rx_q *rxq;
>>> -
>>> - for_each_set_bit(queue_id, &fep->work_rx, FEC_ENET_MAX_RX_QS)
>>> {
>>> - clear_bit(queue_id, &fep->work_rx);
>>> - rxq = fep->rx_queue[FEC_ENET_GET_QUQUE(queue_id)];
>>> - pkt_received += fec_rxq(ndev, fep, rxq, budget -
>>> pkt_received);
>>> - }
>>> - return pkt_received;
>>> -}
>>> -
>>> -static bool
>>> -fec_enet_collect_events(struct fec_enet_private *fep, uint int_events) -{
>>> - if (int_events == 0)
>>> - return false;
>>> -
>>> - if (int_events & FEC_ENET_RXF_0)
>>> - fep->work_rx |= (1 << 2);
>>> - if (int_events & FEC_ENET_RXF_1)
>>> - fep->work_rx |= (1 << 0);
>>> - if (int_events & FEC_ENET_RXF_2)
>>> - fep->work_rx |= (1 << 1);
>>> -
>>> - if (int_events & FEC_ENET_TXF_0)
>>> - fep->work_tx |= (1 << 2);
>>> - if (int_events & FEC_ENET_TXF_1)
>>> - fep->work_tx |= (1 << 0);
>>> - if (int_events & FEC_ENET_TXF_2)
>>> - fep->work_tx |= (1 << 1);
>>> -
>>> - return true;
>>> -}
>>> -
>>> static irqreturn_t
>>> fec_enet_interrupt(int irq, void *dev_id) {
>>> struct net_device *ndev = dev_id;
>>> struct fec_enet_private *fep = netdev_priv(ndev);
>>> - uint int_events;
>>> - irqreturn_t ret = IRQ_NONE;
>>> + uint eir = readl(fep->hwp + FEC_IEVENT);
>>> + uint int_events = eir & readl(fep->hwp + FEC_IMASK);
>>>
>>> - int_events = readl(fep->hwp + FEC_IEVENT);
>>> - writel(int_events, fep->hwp + FEC_IEVENT);
>>> - fec_enet_collect_events(fep, int_events);
>>> -
>>> - if ((fep->work_tx || fep->work_rx) && fep->link) {
>>> - ret = IRQ_HANDLED;
>>> + if (!int_events)
>>> + return IRQ_NONE;
>>>
>>> + if (int_events & (FEC_ENET_RXF | FEC_ENET_TXF)) {
>>> if (napi_schedule_prep(&fep->napi)) {
>>> /* Disable the NAPI interrupts */
>>> writel(FEC_NAPI_IMASK, fep->hwp + FEC_IMASK);
>>> __napi_schedule(&fep->napi);
>>> + int_events &= ~(FEC_ENET_RXF | FEC_ENET_TXF);
>>> + if (!int_events)
>>> + return IRQ_HANDLED;
>>> + } else {
>>> + fep->events |= int_events;
>>> + pr_info("%s: couldn't schedule NAPI\n", __func__);
>>> }
>>> }
>>>
>>> - if (int_events & FEC_ENET_MII) {
>>> - ret = IRQ_HANDLED;
>>> + writel(int_events, fep->hwp + FEC_IEVENT);
>>> + if (int_events & FEC_ENET_MII)
>>> complete(&fep->mdio_done);
>>> - }
>>>
>>> - if (fep->ptp_clock)
>>> + if ((int_events & FEC_ENET_TS_TIMER) && fep->ptp_clock)
>>> fec_ptp_check_pps_event(fep);
>>> -
>> This is error in here. FEC compare timer event is not TS timer.
>>
>>
>
>
> So when should fec_ptp_check_pps_event be called ? On every interrupt ?
Compare event is not showed in EIR register. Need check TCSR, please
see below code.
uint fec_ptp_check_pps_event(struct fec_enet_private *fep)
{
xx
val = readl(fep->hwp + FEC_TCSR(channel));
if (val & FEC_T_TF_MASK) {
}
>
> If napi is active, it is going to be delayed for a very long time.
> Should it be moved to the napi routine?
>
>
>
>
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