From: Jakub Kicinski <kuba@kernel.org>
To: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Heng Qi <hengqi@linux.alibaba.com>, <netdev@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Vladimir Oltean <vladimir.oltean@nxp.com>,
"David S. Miller" <davem@davemloft.net>,
"Jason Wang" <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
vadim.fedorenko@linux.dev
Subject: Re: [PATCH net-next v2 2/2] virtio-net: support dim profile fine-tuning
Date: Wed, 27 Mar 2024 17:32:58 -0700 [thread overview]
Message-ID: <20240327173258.21c031a8@kernel.org> (raw)
In-Reply-To: <556ec006-6157-458d-b9c8-86436cb3199d@intel.com>
On Wed, 27 Mar 2024 15:45:50 +0100 Alexander Lobakin wrote:
> > +/* This is copied from NET_DIM_RX_EQE_PROFILES in DIM library */
> > +#define VIRTNET_DIM_RX_PKTS 256
> > +static struct dim_cq_moder rx_eqe_conf[] = {
> > + {.usec = 1, .pkts = VIRTNET_DIM_RX_PKTS,},
> > + {.usec = 8, .pkts = VIRTNET_DIM_RX_PKTS,},
> > + {.usec = 64, .pkts = VIRTNET_DIM_RX_PKTS,},
> > + {.usec = 128, .pkts = VIRTNET_DIM_RX_PKTS,},
> > + {.usec = 256, .pkts = VIRTNET_DIM_RX_PKTS,}
> > +};
>
> This is wrong.
> This way you will have one global table for ALL the virtio devices in
> the system, while Ethtool performs configuration on a per-netdevice basis.
> What you need is to have 1 dim_cq_moder per each virtio netdevice,
> embedded somewhere into its netdev_priv(). Then
> virtio_dim_{rx,tx}_work() will take profiles from there, not the global
> struct. The global struct can stay here as const to initialize default
> per-netdevice params.
I've been wondering lately if adaptive IRQ moderation isn't exactly
the kind of heuristic we would be best off deferring to BPF.
I have done 0 experiments -- are the thresholds enough
or do more interesting algos come to mind for anyone?
next prev parent reply other threads:[~2024-03-28 0:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-27 9:19 [PATCH net-next v2 0/2] ethtool: provide the dim profile fine-tuning channel Heng Qi
2024-03-27 9:19 ` [PATCH net-next v2 1/2] ethtool: provide customized dim profile management Heng Qi
2024-03-27 9:19 ` [PATCH net-next v2 2/2] virtio-net: support dim profile fine-tuning Heng Qi
2024-03-27 14:45 ` Alexander Lobakin
2024-03-28 0:32 ` Jakub Kicinski [this message]
2024-03-28 2:12 ` Xuan Zhuo
2024-03-28 16:48 ` Jakub Kicinski
2024-03-29 8:56 ` Heng Qi
2024-03-29 15:18 ` Jakub Kicinski
2024-03-28 2:26 ` Heng Qi
2024-03-28 2:02 ` Heng Qi
2024-03-28 7:27 ` Michael S. Tsirkin
2024-03-28 7:27 ` Michael S. Tsirkin
2024-03-28 7:51 ` Heng Qi
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