From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A48CF33689D for ; Fri, 13 Mar 2026 22:07:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773439631; cv=none; b=GfDKD1LTn4TOxb5xv4vqOyd2KkEVZ+TYE69TBFjhiWzClSIqAgY9D/9n99VpbWOlpd5JAcZblzvCDDzIjYWuuU9hlJD+jSL2ouiAM5vFzLLn7AdKbtOLR3H0Bn6rtS7XcWOzDfe+l3RME/b+mRQBNcxPZz9rPzRBGG5PyV3UdDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773439631; c=relaxed/simple; bh=36xZjDqxgbQRJoF9T+tfKZC50MAytjkKOe8z2qmQNKc=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=K7uT51/1Iq0T1GqpvvATPGui8SXQAV8tEuUDqCsxaIumpAnI3EoB3yw8tru7HdgqkBJQiB3N841kPWPPUfnOU0zI3irppXjJKBvf3Bvss2mqOcpKMx71MJJA7h4pvOqTuXMC11PfasjQtwIShZsRxyixc8s/vLFvOwzNz5ifqvU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nuuEtUCl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nuuEtUCl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 30B6FC19421; Fri, 13 Mar 2026 22:07:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773439631; bh=36xZjDqxgbQRJoF9T+tfKZC50MAytjkKOe8z2qmQNKc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nuuEtUClOYvgi5pB/X9IddMd+8PbTcMzUabvZCtelt0Lwkk4jZKg19JPArphJMQHO 85fz/0waIL/PD1pH83U7D3KS0JphaCLKwA5tNClr1IK/9rpo9mgv+aIIgQL7HVAR02 TTzut8L4b5NH9uD5UYYcK8QXSxdWGINPUL0He+2qWq4nM557O7vOcfqPLrGjx8gpDU +szE6/myLqrpegd8LAJk5tCcpgMkxcv6Z04QxxdxVALCWpXpaINd0wz5r1NQmY+Hzb l36rsHwAdAZYCGHzFtiQcjXHEbnKSAIKGgPZPG7hZukrEDMxQKjy+fPKP9Sm5mg9tQ Tdaw7mFW16Zsw== Date: Fri, 13 Mar 2026 15:07:10 -0700 From: Jakub Kicinski To: Eric Dumazet Cc: "David S . Miller" , Paolo Abeni , Simon Horman , Neal Cardwell , Kuniyuki Iwashima , netdev@vger.kernel.org, eric.dumazet@gmail.com Subject: Re: [PATCH net-next] tcp: add cwnd_event_tx_start to tcp_congestion_ops Message-ID: <20260313150710.0edaa6b9@kernel.org> In-Reply-To: <20260313202802.1201129-1-edumazet@google.com> References: <20260313202802.1201129-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 13 Mar 2026 20:28:02 +0000 Eric Dumazet wrote: > (tcp_congestion_ops)->cwnd_event() is called very often, with > @event oscillating between CA_EVENT_TX_START and other values. > > This is not branch prediction friendly. > > Provide a new cwnd_event_tx_start pointer dedicated for CA_EVENT_TX_START. > > Both BBR and CUBIC benefit from this change, since they only care > about CA_EVENT_TX_START. BPF selftest are not happy: 857 progs/tcp_ca_kfunc.c:121:33: error: use of undeclared identifier 'cwnd_event_tx_start' 121 | .cwnd_event_tx_start = (void *)cwnd_event_tx_start, | ^~~~~~~~~~~~~~~~~~~ -- pw-bot: cr