From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id C4DED986319 for ; Sun, 12 Feb 2023 21:08:45 +0000 (UTC) Date: Sun, 12 Feb 2023 16:08:36 -0500 From: "Michael S. Tsirkin" Message-ID: <20230212160656-mutt-send-email-mst@kernel.org> References: <20230210070130.21811-1-hengqi@linux.alibaba.com> <601ef040-bac2-dd6d-b32c-2029be17c071@linux.alibaba.com> <20230212152122-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: Subject: [virtio-dev] Re: [virtio-comment] Re: [PATCH v2] virtio-net: support the virtqueue coalescing moderation Content-Type: text/plain; charset=us-ascii Content-Disposition: inline To: Alvaro Karsz Cc: Heng Qi , Parav Pandit , "virtio-comment@lists.oasis-open.org" , "virtio-dev@lists.oasis-open.org" , Jason Wang , Xuan Zhuo List-ID: On Sun, Feb 12, 2023 at 10:53:50PM +0200, Alvaro Karsz wrote: > > I'm not sure the specific property is even a feature and not a bug. > > One can argue e.g. that ethtool should fail with EBUSY rather > > than being silently overwritten. > > Thats why I feel this kind of policy is best set by driver. > > When you write "set by driver", you mean that [X] the spec needs to > define the driver behavior in this case, or that [Y] every driver > should decide what's best? > I'll answer to [X], if you meant [Y] the following part is not relevant. Y. > If we talk implementation here, I would probably implement it like that: > > net_dim_start_tx: > set_ethtool_blocking_bool > save_current_coalescing_params # Maybe? > clear_all_tx_coalescing_params # NOTF_COAL_TX_SET 0 > do_net_dim > > net_dim_stop_tx: > restore_prev_ethtool_coalesing_params > clear_ethtool_blocking_bool > > It's reasonable to assume that sending a ethtool set coalesce when > netdim is operating will affect the performance. > > But, windows' virtio_net driver may want to use _CTRL_NOTF_COAL_TX_SET > in its adaptive algorithm, and may have no userspace tool to configure > these parameters. > If we force the driver to clear/block some commands while using > others, we may do more harm than good in windows' case. > > This is just my personal perspective. > > I think that this is an important feature either way. --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org