From: Bing Zhao <bingz@nvidia.com>
To: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Cc: dpdk stable <stable@dpdk.org>,
Slava Ovsiienko <viacheslavo@nvidia.com>,
Matan Azrad <matan@nvidia.com>
Subject: Re: [dpdk-stable] [PATCH 19.11 6/6] net/mlx5: fix multi-segment inline for the first segments
Date: Tue, 17 Aug 2021 13:55:41 +0000 [thread overview]
Message-ID: <CH0PR12MB50411003DBF2EB5836D7EC7FD0FE9@CH0PR12MB5041.namprd12.prod.outlook.com> (raw)
In-Reply-To: <CAATJJ0+RiHWfOMo+D062hut3P5OVtGA5VadVsbjZTDoZ1XFWgg@mail.gmail.com>
Hi Christian,
I talked with Slava, some feature is not supported in LTS 19.11. So please discard this commit.
And I sent a v2 to reply the original email thread.
Thanks
> -----Original Message-----
> From: Christian Ehrhardt <christian.ehrhardt@canonical.com>
> Sent: Tuesday, August 17, 2021 7:55 PM
> To: Bing Zhao <bingz@nvidia.com>
> Cc: dpdk stable <stable@dpdk.org>; Slava Ovsiienko
> <viacheslavo@nvidia.com>; Matan Azrad <matan@nvidia.com>
> Subject: Re: [PATCH 19.11 6/6] net/mlx5: fix multi-segment inline
> for the first segments
>
> External email: Use caution opening links or attachments
>
>
> On Mon, Aug 16, 2021 at 6:30 PM Bing Zhao <bingz@nvidia.com> wrote:
> >
> > From: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> >
> > [ upstream commit ec837ad0fc7c6df4912cc2706b9cd54b225f4a34 ]
>
> While not applying this causes build fails on some platforms.
>
> Looks like:
> [ 974s] ../drivers/net/mlx5/mlx5_rxtx.c: In function
> ‘mlx5_tx_packet_multi_inline’:
> [ 974s] ../drivers/net/mlx5/mlx5_rxtx.c:3356:31: error:
> ‘PKT_TX_DYNF_NOINLINE’ undeclared (first use in this function)
> [ 974s] 3356 | } else if (mbuf->ol_flags & PKT_TX_DYNF_NOINLINE
> ||
> [ 974s] | ^~~~~~~~~~~~~~~~~~~~
> [ 974s] ../drivers/net/mlx5/mlx5_rxtx.c:3356:31: note: each
> undeclared identifier is reported only once for each function it
> appears in [ 974s] ninja: build stopped: subcommand failed.
>
> And indeed this is the only occurrence
>
> $ grep -Hrn PKT_TX_DYNF_NOINLINE *
> drivers/net/mlx5/mlx5_rxtx.c:3356: } else if (mbuf->ol_flags &
> PKT_TX_DYNF_NOINLINE ||
>
> Since it only happens on some releases I'd assume the other
> arch/distros just do not build this?
> It seems to only affect those building with meson.
>
> For now I've removed this patch again from 19.11 - please have a
> look and let me know if you'll provide a refreshed backport.
>
>
>
> > Before 19.08 release the Tx burst routines of mlx5 PMD provided
> data
> > inline for the first short segments of the multi-segment packets.
> In
> > the release 19.08 mlx5 Tx datapath was refactored and this
> behavior
> > was broken, affecting the performance.
> >
> > For example, the T-Rex traffic generator might use small leading
> > segments to handle packet headers and performance degradation was
> > noticed.
> >
> > If the first segments of the multi-segment packet are short and
> the
> > overall length is below the inline threshold it should be inline
> into
> > the WQE to fix the performance.
> >
> > Fixes: 18a1c20044c0 ("net/mlx5: implement Tx burst template")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> > Signed-off-by: Bing Zhao <bingz@nvidia.com>
> > ---
> > drivers/net/mlx5/mlx5_rxtx.c | 27 +++++++++++++--------------
> > 1 file changed, 13 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5_rxtx.c
> > b/drivers/net/mlx5/mlx5_rxtx.c index 73dbf68d2b..094e359e55 100644
> > --- a/drivers/net/mlx5/mlx5_rxtx.c
> > +++ b/drivers/net/mlx5/mlx5_rxtx.c
> > @@ -3336,6 +3336,8 @@ mlx5_tx_packet_multi_inline(struct
> mlx5_txq_data *restrict txq,
> > unsigned int nxlen;
> > uintptr_t start;
> >
> > + mbuf = loc->mbuf;
> > + nxlen = rte_pktmbuf_data_len(mbuf);
> > /*
> > * Packet length exceeds the allowed inline
> > * data length, check whether the minimal @@ -
> 3345,27
> > +3347,23 @@ mlx5_tx_packet_multi_inline(struct mlx5_txq_data
> *restrict txq,
> > assert(txq->inlen_mode >=
> MLX5_ESEG_MIN_INLINE_SIZE);
> > assert(txq->inlen_mode <= txq->inlen_send);
> > inlen = txq->inlen_mode;
> > - } else {
> > - if (!vlan || txq->vlan_en) {
> > - /*
> > - * VLAN insertion will be done
> inside by HW.
> > - * It is not utmost effective -
> VLAN flag is
> > - * checked twice, but we should
> proceed the
> > - * inlining length correctly and
> take into
> > - * account the VLAN header being
> inserted.
> > - */
> > - return mlx5_tx_packet_multi_send
> > - (txq, loc,
> olx);
> > - }
> > + } else if (vlan && !txq->vlan_en) {
> > + /*
> > + * VLAN insertion is requested and
> hardware does not
> > + * support the offload, will do with
> software inline.
> > + */
> > inlen = MLX5_ESEG_MIN_INLINE_SIZE;
> > + } else if (mbuf->ol_flags & PKT_TX_DYNF_NOINLINE
> ||
> > + nxlen > txq->inlen_send) {
> > + return mlx5_tx_packet_multi_send(txq, loc,
> olx);
> > + } else {
> > + goto do_first;
> > }
> > /*
> > * Now we know the minimal amount of data is
> requested
> > * to inline. Check whether we should inline the
> buffers
> > * from the chain beginning to eliminate some
> mbufs.
> > */
> > - mbuf = loc->mbuf;
> > - nxlen = rte_pktmbuf_data_len(mbuf);
> > if (unlikely(nxlen <= txq->inlen_send)) {
> > /* We can inline first mbuf at least. */
> > if (nxlen < inlen) { @@ -3387,6 +3385,7 @@
> > mlx5_tx_packet_multi_inline(struct mlx5_txq_data *restrict txq,
> > goto do_align;
> > }
> > }
> > +do_first:
> > do {
> > inlen = nxlen;
> > mbuf = NEXT(mbuf);
> > --
> > 2.21.0
> >
>
>
> --
> Christian Ehrhardt
> Staff Engineer, Ubuntu Server
> Canonical Ltd
next prev parent reply other threads:[~2021-08-17 13:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-16 16:29 [dpdk-stable] [PATCH 19.11 0/6] Cumulative fixes for stable 19.11 Bing Zhao
2021-08-16 16:29 ` [dpdk-stable] [PATCH 19.11 1/6] app/testpmd: fix offloads for newly attached port Bing Zhao
2021-08-16 16:29 ` [dpdk-stable] [PATCH 19.11 2/6] common/mlx5: fix compatibility with OFED port query API Bing Zhao
2021-08-16 16:29 ` [dpdk-stable] [PATCH 19.11 3/6] net/mlx5: fix switchdev mode recognition Bing Zhao
2021-08-16 16:29 ` [dpdk-stable] [PATCH 19.11 4/6] net/mlx5: fix RoCE LAG bond device probing Bing Zhao
2021-08-16 16:29 ` [dpdk-stable] [PATCH 19.11 5/6] common/mlx5: use new port query API if available Bing Zhao
2021-08-16 16:29 ` [dpdk-stable] [PATCH 19.11 6/6] net/mlx5: fix multi-segment inline for the first segments Bing Zhao
2021-08-17 11:55 ` Christian Ehrhardt
2021-08-17 13:55 ` Bing Zhao [this message]
2021-08-17 9:42 ` [dpdk-stable] [PATCH 19.11 0/6] Cumulative fixes for stable 19.11 Christian Ehrhardt
2021-08-17 13:54 ` [dpdk-stable] [PATCH 19.11 v2] net/mlx5: fix multi-segment inline for the first segments Bing Zhao
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