From: Jiri Pirko <jiri@resnulli.us>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, jasowang@redhat.com,
xuanzhuo@linux.alibaba.com, virtualization@lists.linux.dev,
ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org,
john.fastabend@gmail.com
Subject: Re: [patch net-next] virtio_net: add support for Byte Queue Limits
Date: Fri, 10 May 2024 13:36:35 +0200 [thread overview]
Message-ID: <Zj4Gw52pTbg01vvR@nanopsycho.orion> (raw)
In-Reply-To: <20240510072431-mutt-send-email-mst@kernel.org>
Fri, May 10, 2024 at 01:27:08PM CEST, mst@redhat.com wrote:
>On Fri, May 10, 2024 at 01:11:49PM +0200, Jiri Pirko wrote:
>> Fri, May 10, 2024 at 12:52:52PM CEST, mst@redhat.com wrote:
>> >On Fri, May 10, 2024 at 12:37:15PM +0200, Jiri Pirko wrote:
>> >> Thu, May 09, 2024 at 04:28:12PM CEST, mst@redhat.com wrote:
>> >> >On Thu, May 09, 2024 at 03:31:56PM +0200, Jiri Pirko wrote:
>> >> >> Thu, May 09, 2024 at 02:41:39PM CEST, mst@redhat.com wrote:
>> >> >> >On Thu, May 09, 2024 at 01:46:15PM +0200, Jiri Pirko wrote:
>> >> >> >> From: Jiri Pirko <jiri@nvidia.com>
>> >> >> >>
>> >> >> >> Add support for Byte Queue Limits (BQL).
>> >> >> >>
>> >> >> >> Signed-off-by: Jiri Pirko <jiri@nvidia.com>
>> >> >> >
>> >> >> >Can we get more detail on the benefits you observe etc?
>> >> >> >Thanks!
>> >> >>
>> >> >> More info about the BQL in general is here:
>> >> >> https://lwn.net/Articles/469652/
>> >> >
>> >> >I know about BQL in general. We discussed BQL for virtio in the past
>> >> >mostly I got the feedback from net core maintainers that it likely won't
>> >> >benefit virtio.
>> >>
>> >> Do you have some link to that, or is it this thread:
>> >> https://lore.kernel.org/netdev/21384cb5-99a6-7431-1039-b356521e1bc3@redhat.com/
>> >
>> >
>> >A quick search on lore turned up this, for example:
>> >https://lore.kernel.org/all/a11eee78-b2a1-3dbc-4821-b5f4bfaae819@gmail.com/
>>
>> Says:
>> "Note that NIC with many TX queues make BQL almost useless, only adding extra
>> overhead."
>>
>> But virtio can have one tx queue, I guess that could be quite common
>> configuration in lot of deployments.
>
>Not sure we should worry about performance for these though.
Well, queues may be scarce resource sometimes, even in those cases, you
want to perform.
>What I am saying is this should come with some benchmarking
>results.
Sure, I got the message.
>
>
>>
>> >
>> >
>> >
>> >
>> >> I don't see why virtio should be any different from other
>> >> drivers/devices that benefit from bql. HOL blocking is the same here are
>> >> everywhere.
>> >>
>> >> >
>> >> >So I'm asking, what kind of benefit do you observe?
>> >>
>> >> I don't have measurements at hand, will attach them to v2.
>> >>
>> >> Thanks!
>> >>
>> >> >
>> >> >--
>> >> >MST
>> >> >
>> >
>
next prev parent reply other threads:[~2024-05-10 11:36 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 11:46 [patch net-next] virtio_net: add support for Byte Queue Limits Jiri Pirko
2024-05-09 12:41 ` Michael S. Tsirkin
2024-05-09 13:31 ` Jiri Pirko
2024-05-09 14:28 ` Michael S. Tsirkin
2024-05-10 4:25 ` Jason Wang
2024-05-10 10:37 ` Jiri Pirko
2024-05-10 10:52 ` Michael S. Tsirkin
2024-05-10 11:11 ` Jiri Pirko
2024-05-10 11:27 ` Michael S. Tsirkin
2024-05-10 11:36 ` Jiri Pirko [this message]
2024-05-15 7:34 ` Jiri Pirko
2024-05-15 8:20 ` Michael S. Tsirkin
2024-05-15 10:12 ` Jiri Pirko
2024-05-15 12:54 ` Jiri Pirko
2024-05-16 4:48 ` Jason Wang
2024-05-16 10:54 ` Jiri Pirko
2024-05-16 12:31 ` Michael S. Tsirkin
2024-05-16 15:25 ` Jiri Pirko
2024-05-16 19:04 ` Michael S. Tsirkin
2024-05-17 7:52 ` Jiri Pirko
2024-05-10 4:25 ` Jason Wang
2024-05-10 7:11 ` Heng Qi
2024-05-10 10:35 ` Jiri Pirko
2024-05-20 12:48 ` Jiri Pirko
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