Re: [PATCH net-next v9 0/5] TLS read_sock performance scalability

Chuck Lever
2026-05-04T15:59:35Z

On Mon, May 4, 2026, at 3:33 PM, Sabrina Dubroca wrote:
> 2026-05-03, 21:34:01 +0200, Chuck Lever wrote:
>> On 5/3/26 3:04 AM, Jakub Kicinski wrote:
>> > On Wed, 29 Apr 2026 17:48:07 -0400 Chuck Lever wrote:
>> >> I'd like to encourage in-kernel kTLS consumers (i.e., NFS and
>> >> NVMe/TCP) to coalesce on the use of read_sock. When I suggested
>> >> this to Hannes, he reported a few performance scalability issues
>> >> with read_sock.
>> >
>> > Meaning, this series achieves.. what right now?
>> > I mean - the headline is "performance scalability" and there's no
>> > performance testing result in any of the messages :S
>> > Patch 5 for instance "seems logical" but how much difference does
>> > it make?
>>
>> The cover Subject: line has not been changed so all the revisions of
>> this series can be located easily.
>
> (not to bikeshed, links to lore also do that)
>
>> The cover letter makes it clear that the series is now only a clean-up
>> series. Since async_capable is set to false for TLSv1.3, there is no
>> performance benefit to these changes, so I don't intend to post a
>> motivation for it based on performance.
>
> Maybe I misunderstood, but I thought there was a somewhat noticeable
> benefit to the "suppress spurious wakeups" patch (not +20%, but at
> least improved behavior for some users of kTLS), and maybe the "flush
> backlog" one.
>
> Patch 2 may still be beneficial (though it's now mixing 2 separate
> changes), and patch 1 is a very reasonable code cleanup.
>
> Patch 4 does feel like a pretty large amount of churn if it has no
> observable benefit.

There is potential benefit to eliminating spurious wake-ups,
but nothing I've found to be observable at the application
level.

>> We'd really like
>> to get TLS KeyUpdate working for in-kernel TLS consumers, so anything
>> that can move this process forward is welcome.
>
> But net/tls doesn't need any changes for that, right?

>> 1. The in-kernel TLS consumers need to reliably and securely handle TLS
>> Alerts. That is coming in the next series I plan to post.

This series will make changes to net/tls/.

--
Chuck Lever