netdev - Re: [PATCH net-next v2 2/2] virtio-net: support dim profile fine-tuning

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8bbbcd8b-b812-4e65-8169-73ffc5479eef@linux.alibaba.com>
Date: Thu, 28 Mar 2024 10:02:31 +0800
From: Heng Qi <hengqi@...ux.alibaba.com>
To: Alexander Lobakin <aleksander.lobakin@...el.com>
Cc: netdev@...r.kernel.org, Jakub Kicinski <kuba@...nel.org>,
 Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
 Vladimir Oltean <vladimir.oltean@....com>,
 "David S. Miller" <davem@...emloft.net>, Jason Wang <jasowang@...hat.com>,
 "Michael S. Tsirkin" <mst@...hat.com>, Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Subject: Re: [PATCH net-next v2 2/2] virtio-net: support dim profile
 fine-tuning



在 2024/3/27 下午10:45, Alexander Lobakin 写道:
> From: Heng Qi <hengqi@...ux.alibaba.com>
> Date: Wed, 27 Mar 2024 17:19:06 +0800
>
>> Virtio-net has different types of back-end device
>> implementations. In order to effectively optimize
>> the dim library's gains for different device
>> implementations, let's use the new interface params
>> to fine-tune the profile list.
> Nice idea, but
>
>> Signed-off-by: Heng Qi <hengqi@...ux.alibaba.com>
>> ---
>>   drivers/net/virtio_net.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++--
>>   1 file changed, 52 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index e709d44..9b6c727 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -57,6 +57,16 @@
>>   
>>   #define VIRTNET_DRIVER_VERSION "1.0.0"
>>   
>> +/* 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.

You are right. Good catch!

Thanks,
Heng

>> +
>>   static const unsigned long guest_offloads[] = {
>>   	VIRTIO_NET_F_GUEST_TSO4,
>>   	VIRTIO_NET_F_GUEST_TSO6,
> Thanks,
> Olek