From: Bobby Eshleman <bobbyeshleman@gmail.com>
To: Simon Horman <horms@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Kuniyuki Iwashima <kuniyu@google.com>,
Willem de Bruijn <willemb@google.com>,
Neal Cardwell <ncardwell@google.com>,
David Ahern <dsahern@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Stanislav Fomichev <sdf@fomichev.me>,
Mina Almasry <almasrymina@google.com>,
Bobby Eshleman <bobbyeshleman@meta.com>
Subject: Re: [PATCH net-next v3 0/2] net: devmem: improve cpu cost of RX token management
Date: Fri, 26 Sep 2025 09:45:42 -0700 [thread overview]
Message-ID: <aNbDNr8ZHw5AzVHQ@devvm11784.nha0.facebook.com> (raw)
In-Reply-To: <aNa3ValQeGEm_WGb@horms.kernel.org>
On Fri, Sep 26, 2025 at 04:55:01PM +0100, Simon Horman wrote:
> On Fri, Sep 26, 2025 at 08:02:52AM -0700, Bobby Eshleman wrote:
> > This series improves the CPU cost of RX token management by replacing
> > the xarray allocator with an niov array and a uref field in niov.
> >
> > Improvement is ~5% per RX user thread.
> >
> > Two other approaches were tested, but with no improvement. Namely, 1)
> > using a hashmap for tokens and 2) keeping an xarray of atomic counters
> > but using RCU so that the hotpath could be mostly lockless. Neither of
> > these approaches proved better than the simple array in terms of CPU.
> >
> > Running with a NCCL workload is still TODO, but I will follow up on this
> > thread with those results when done.
> >
> > Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
>
> Hi Bobby,
>
> Unfortunately this patchset doesn't apply cleanly to net-next.
> So you'll need to rebase and repost at some point.
>
> --
> pw-bot: changes-requested
Got it, just resent and added this check to my automation, thanks!
Best,
Bobby
prev parent reply other threads:[~2025-09-26 16:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-26 15:02 [PATCH net-next v3 0/2] net: devmem: improve cpu cost of RX token management Bobby Eshleman
2025-09-26 15:02 ` [PATCH net-next v3 1/2] net: devmem: rename tx_vec to vec in dmabuf binding Bobby Eshleman
2025-09-26 15:02 ` [PATCH net-next v3 2/2] net: devmem: use niov array for token management Bobby Eshleman
2025-09-26 15:55 ` [PATCH net-next v3 0/2] net: devmem: improve cpu cost of RX " Simon Horman
2025-09-26 16:45 ` Bobby Eshleman [this message]
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