RE: [PATCH 09/10] dpaa_eth: add support for hardware timestamping
Hi Richard, > -Original Message- > From: Richard Cochran [mailto:richardcoch...@gmail.com] > Sent: Tuesday, June 5, 2018 9:58 PM > To: Y.b. Lu > Cc: net...@vger.kernel.org; Madalin-cristian Bucur > ; Rob Herring ; Shawn Guo > ; David S . Miller ; > devicet...@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; > linux-arm-ker...@lists.infradead.org; linux-ker...@vger.kernel.org > Subject: Re: [PATCH 09/10] dpaa_eth: add support for hardware timestamping > > On Tue, Jun 05, 2018 at 03:35:28AM +, Y.b. Lu wrote: > > [Y.b. Lu] Actually these timestamping codes affected DPAA networking > performance in our previous performance test. > > That's why we used ifdef for it. > > How much does time stamping hurt performance? > > If the time stamping is compiled in but not enabled at run time, does it still > affect performace? [Y.b. Lu] I can't remember and find the old data since it had been a long time. I just did the iperf test today between two 10G ports. I didn’t see any performance changes with timestamping code So, let's me remove the ifdef in next version. Thanks a lot. > > Thanks, > Richard
Re: [PATCH 09/10] dpaa_eth: add support for hardware timestamping
On Tue, Jun 05, 2018 at 03:35:28AM +, Y.b. Lu wrote: > [Y.b. Lu] Actually these timestamping codes affected DPAA networking > performance in our previous performance test. > That's why we used ifdef for it. How much does time stamping hurt performance? If the time stamping is compiled in but not enabled at run time, does it still affect performace? Thanks, Richard
RE: [PATCH 09/10] dpaa_eth: add support for hardware timestamping
Hi Richard,
> -Original Message-
> From: Richard Cochran [mailto:richardcoch...@gmail.com]
> Sent: Monday, June 4, 2018 9:49 PM
> To: Y.b. Lu
> Cc: net...@vger.kernel.org; Madalin-cristian Bucur
> ; Rob Herring ; Shawn Guo
> ; David S . Miller ;
> devicet...@vger.kernel.org; linuxppc-dev@lists.ozlabs.org;
> linux-arm-ker...@lists.infradead.org; linux-ker...@vger.kernel.org
> Subject: Re: [PATCH 09/10] dpaa_eth: add support for hardware timestamping
>
> On Mon, Jun 04, 2018 at 03:08:36PM +0800, Yangbo Lu wrote:
>
> > +if FSL_DPAA_ETH
> > +config FSL_DPAA_ETH_TS
> > + bool "DPAA hardware timestamping support"
> > + select PTP_1588_CLOCK_QORIQ
> > + default n
> > + help
> > + Enable DPAA hardware timestamping support.
> > + This option is useful for applications to get
> > + hardware time stamps on the Ethernet packets
> > + using the SO_TIMESTAMPING API.
> > +endif
>
> You should drop this #ifdef. In general, if a MAC supports time stamping and
> PHC, then the driver support should simply be compiled in.
>
> [ When time stamping incurs a large run time performance penalty to
> non-PTP users, then it might make sense to have a Kconfig option to
> disable it, but that doesn't appear to be the case here. ]
[Y.b. Lu] Actually these timestamping codes affected DPAA networking
performance in our previous performance test.
That's why we used ifdef for it.
>
> > @@ -1615,6 +1635,24 @@ static int dpaa_eth_refill_bpools(struct
> dpaa_priv *priv)
> > skbh = (struct sk_buff **)phys_to_virt(addr);
> > skb = *skbh;
> >
> > +#ifdef CONFIG_FSL_DPAA_ETH_TS
> > + if (priv->tx_tstamp &&
> > + skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
>
> This condition fits on one line easily.
[Y.b. Lu] Right. I will use one line in next version.
>
> > + struct skb_shared_hwtstamps shhwtstamps;
> > + u64 ns;
>
> Local variables belong at the top of the function.
[Y.b. Lu] Ok, will move them to the top in next verison.
>
> > + memset(, 0, sizeof(shhwtstamps));
> > +
> > + if (!dpaa_get_tstamp_ns(priv->net_dev, ,
> > + priv->mac_dev->port[TX],
> > + (void *)skbh)) {
> > + shhwtstamps.hwtstamp = ns_to_ktime(ns);
> > + skb_tstamp_tx(skb, );
> > + } else {
> > + dev_warn(dev, "dpaa_get_tstamp_ns failed!\n");
> > + }
> > + }
> > +#endif
> > if (unlikely(qm_fd_get_format(fd) == qm_fd_sg)) {
> > nr_frags = skb_shinfo(skb)->nr_frags;
> > dma_unmap_single(dev, addr, qm_fd_get_offset(fd) + @@ -2086,6
> > +2124,14 @@ static int dpaa_start_xmit(struct sk_buff *skb, struct
> net_device *net_dev)
> > if (unlikely(err < 0))
> > goto skb_to_fd_failed;
> >
> > +#ifdef CONFIG_FSL_DPAA_ETH_TS
> > + if (priv->tx_tstamp &&
> > + skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
>
> One line please.
[Y.b. Lu] No problem.
>
> > + fd.cmd |= FM_FD_CMD_UPD;
> > + skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
> > + }
> > +#endif
> > +
> > if (likely(dpaa_xmit(priv, percpu_stats, queue_mapping, ) == 0))
> > return NETDEV_TX_OK;
> >
>
> Thanks,
> Richard
Re: [PATCH 09/10] dpaa_eth: add support for hardware timestamping
On Mon, Jun 04, 2018 at 03:08:36PM +0800, Yangbo Lu wrote:
> +if FSL_DPAA_ETH
> +config FSL_DPAA_ETH_TS
> + bool "DPAA hardware timestamping support"
> + select PTP_1588_CLOCK_QORIQ
> + default n
> + help
> + Enable DPAA hardware timestamping support.
> + This option is useful for applications to get
> + hardware time stamps on the Ethernet packets
> + using the SO_TIMESTAMPING API.
> +endif
You should drop this #ifdef. In general, if a MAC supports time
stamping and PHC, then the driver support should simply be compiled
in.
[ When time stamping incurs a large run time performance penalty to
non-PTP users, then it might make sense to have a Kconfig option to
disable it, but that doesn't appear to be the case here. ]
> @@ -1615,6 +1635,24 @@ static int dpaa_eth_refill_bpools(struct dpaa_priv
> *priv)
> skbh = (struct sk_buff **)phys_to_virt(addr);
> skb = *skbh;
>
> +#ifdef CONFIG_FSL_DPAA_ETH_TS
> + if (priv->tx_tstamp &&
> + skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
This condition fits on one line easily.
> + struct skb_shared_hwtstamps shhwtstamps;
> + u64 ns;
Local variables belong at the top of the function.
> + memset(, 0, sizeof(shhwtstamps));
> +
> + if (!dpaa_get_tstamp_ns(priv->net_dev, ,
> + priv->mac_dev->port[TX],
> + (void *)skbh)) {
> + shhwtstamps.hwtstamp = ns_to_ktime(ns);
> + skb_tstamp_tx(skb, );
> + } else {
> + dev_warn(dev, "dpaa_get_tstamp_ns failed!\n");
> + }
> + }
> +#endif
> if (unlikely(qm_fd_get_format(fd) == qm_fd_sg)) {
> nr_frags = skb_shinfo(skb)->nr_frags;
> dma_unmap_single(dev, addr, qm_fd_get_offset(fd) +
> @@ -2086,6 +2124,14 @@ static int dpaa_start_xmit(struct sk_buff *skb, struct
> net_device *net_dev)
> if (unlikely(err < 0))
> goto skb_to_fd_failed;
>
> +#ifdef CONFIG_FSL_DPAA_ETH_TS
> + if (priv->tx_tstamp &&
> + skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
One line please.
> + fd.cmd |= FM_FD_CMD_UPD;
> + skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
> + }
> +#endif
> +
> if (likely(dpaa_xmit(priv, percpu_stats, queue_mapping, ) == 0))
> return NETDEV_TX_OK;
>
Thanks,
Richard
