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]
Date:   Mon, 6 Mar 2017 17:21:32 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        netdev@...r.kernel.org
Cc:     mst@...hat.com, Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH net-next RFC 2/4] virtio-net: transmit napi



On 2017年03月03日 22:39, Willem de Bruijn wrote:
> From: Willem de Bruijn <willemb@...gle.com>
>
> Convert virtio-net to a standard napi tx completion path. This enables
> better TCP pacing using TCP small queues and increases single stream
> throughput.
>
> The virtio-net driver currently cleans tx descriptors on transmission
> of new packets in ndo_start_xmit. Latency depends on new traffic, so
> is unbounded. To avoid deadlock when a socket reaches its snd limit,
> packets are orphaned on tranmission. This breaks socket backpressure,
> including TSQ.
>
> Napi increases the number of interrupts generated compared to the
> current model, which keeps interrupts disabled as long as the ring
> has enough free descriptors. Keep tx napi optional for now. Follow-on
> patches will reduce the interrupt cost.
>
> Signed-off-by: Willem de Bruijn <willemb@...gle.com>
> ---
>   drivers/net/virtio_net.c | 73 ++++++++++++++++++++++++++++++++++++++++--------
>   1 file changed, 61 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 8c21e9a4adc7..9a9031640179 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -33,6 +33,8 @@
>   static int napi_weight = NAPI_POLL_WEIGHT;
>   module_param(napi_weight, int, 0444);
>   
> +static int napi_tx_weight = NAPI_POLL_WEIGHT;
> +

Maybe we should use module_param for this? Or in the future, use 
tx-frames-irq for a per-device configuration.

Thanks

Powered by blists - more mailing lists