From: David Marchand <david.marchand@redhat.com>
To: Marvin Liu <yong.liu@intel.com>,
Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Xia, Chenbo" <chenbo.xia@intel.com>, dev <dev@dpdk.org>,
"Richardson, Bruce" <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH] net/virtio: enable packet data prefetch on x86
Date: Thu, 12 Nov 2020 09:57:47 +0100 [thread overview]
Message-ID: <CAJFAV8zwOabFw6ithVNMs-YvJi+J-HW1zQfe3cQcPyaYUWb74w@mail.gmail.com> (raw)
In-Reply-To: <ae30534a-2a6f-d295-de42-8844c1cae091@redhat.com>
On Thu, Nov 12, 2020 at 9:48 AM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
> On 11/11/20 4:40 PM, Marvin Liu wrote:
> > Data prefetch instruction can preload data into cpu’s hierarchical
> > cache before data access. Virtio datapath utilized this feature for
> > data access acceleration. As config RTE_PMD_PACKET_PREFETCH was
> > discarded, now packet data prefetch is enabled based on architecture.
> >
> > Signed-off-by: Marvin Liu <yong.liu@intel.com>
> >
> > diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> > index 42c4c9882..0196290a5 100644
> > --- a/drivers/net/virtio/virtqueue.h
> > +++ b/drivers/net/virtio/virtqueue.h
> > @@ -106,7 +106,7 @@ virtqueue_store_flags_packed(struct vring_packed_desc *dp,
> > dp->flags = flags;
> > }
> > }
> > -#ifdef RTE_PMD_PACKET_PREFETCH
> > +#if defined(RTE_ARCH_X86)
> > #define rte_packet_prefetch(p) rte_prefetch1(p)
> > #else
> > #define rte_packet_prefetch(p) do {} while(0)
> >
>
> Thanks for catching this issue.
> I agree it should be re-enabled by default, and not only on X86, not
> only on Virtio PMD.
>
> AFAICS, prefetch was enabled for all platforms before the switch to
> Meson, so I see it as an involuntary change that needs to be reverted.
Yes and this will also solve https://patchwork.dpdk.org/patch/83468/.
Thanks.
--
David Marchand
next prev parent reply other threads:[~2020-11-12 8:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 15:40 Marvin Liu
2020-11-11 15:45 ` David Marchand
2020-11-11 15:53 ` Bruce Richardson
2020-11-11 15:56 ` David Marchand
2020-11-12 8:48 ` Maxime Coquelin
2020-11-12 8:57 ` David Marchand [this message]
2020-11-13 1:20 ` Liu, Yong
2020-11-13 7:27 ` David Marchand
2020-11-13 12:21 ` Liu, Yong
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