From: Simon Horman <horms@kernel.org>
To: Bobby Eshleman <bobbyeshleman@gmail.com>
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 16:55:01 +0100 [thread overview]
Message-ID: <aNa3ValQeGEm_WGb@horms.kernel.org> (raw)
In-Reply-To: <20250926-scratch-bobbyeshleman-devmem-tcp-token-upstream-v3-0-084b46bda88f@meta.com>
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
next prev parent reply other threads:[~2025-09-26 15:55 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 ` Simon Horman [this message]
2025-09-26 16:45 ` [PATCH net-next v3 0/2] net: devmem: improve cpu cost of RX " Bobby Eshleman
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