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 7E8371F1503 for ; Tue, 21 Jan 2025 12:51:27 +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=1737463887; cv=none; b=lxjLbLGLWBiF4TDgUJsYx0ASBqpY0j+srp23ItfRsH09gPFJ3wAyapbooOLPUVXJpjxyB8pCpOaD01BwqvAg/uNME9ct/bFzeCNnejWAsPyDQBOPWpAp+F5BlPPc2OGFDDs/vMzZMzh38MOtWPjOAuhokWgloJFFMuszqw/jh1Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737463887; c=relaxed/simple; bh=AQAB22mqhB1zQtLhuSvyO1zMhf9LsRH3MKVRpXJJHd4=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=B8wqVo38ZQZvD9f1l2+KuOf2WUnHwkIsaS28Q23nuEOO6rkLWoVA4vtyDrMy/YNbvZ7P6TBqcWjKmCHbGlEqB0meEgOhpKaboPxoJdoadEi0b0ZpcOhHhOKN1FQCxLCKO+XSZ/Wznkvmb+c+jLSjjYBI9qDRbmw6s6DmDLoxeIA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ej3h+SDQ; 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="ej3h+SDQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D93BFC4CEDF; Tue, 21 Jan 2025 12:51:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737463886; bh=AQAB22mqhB1zQtLhuSvyO1zMhf9LsRH3MKVRpXJJHd4=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=ej3h+SDQoDSlgTpuKzbq7ZFLeTQSz1dwvhl/tlWyEbNbH8YZvG9lhdy5dZrGg+W3w OC5gm9FtH6cjdI3b2/Wb9kdGBVV52vY9e1jkbq2+2Nd8z12O6Gzd4xSXwZVzB617Cx QWsINtFxZEJZTs5sgYj+KUuePtwa7mfFmRkMUHJq/UxRSsj4s68QgsAR32yDjyY73o AoGK1rRMa4utHmlwcvExLepXCi/TLh6nkVy985WqTB5eOVnLrlBEO0Ct5EWjtdu6UQ BysqSj+nmzj+YvcC/nlRTizzalAp5cHV7YND5fPOpcz9BMnZ1rpxMeFuGHZagRPrt2 JH1wynjp7GkUw== From: Andreas Hindborg To: "Jan Kara" Cc: , , "Jens Axboe" , "Matthew Wilcox" , "Luis Chamberlain" , "Miguel Ojeda" Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Rust block layer abstractions and benchmark strategies In-Reply-To: (Jan Kara's message of "Tue, 21 Jan 2025 13:04:30 +0100") References: <871pwwctcj.fsf@kernel.org> User-Agent: mu4e 1.12.7; emacs 29.4 Date: Tue, 21 Jan 2025 13:51:11 +0100 Message-ID: <87sepcba9s.fsf@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Hi Jan, "Jan Kara" writes: > Hi! > > On Tue 21-01-25 12:13:48, Andreas Hindborg via Lsf-pc wrote: >> I would like to propose that we have a session on Rust in the block >> layer again this year. Specifically I would like to discuss some rather >> puzzling results I observe when I benchmark the C and Rust null block >> drivers. I did a write up of the challenges I face at [1]. The >> observations are not tied to rust, they also manifest in the C driver. > > The results are indeed somewhat curious. One factor I didn't see addressed > in your blog is CPU scheduling. I've seen in the past cases where IO tasks > were getting migrated across cores leading to jumps in perfomance. Did you > try binding fio jobs to one CPU each? Yes, I am pinning the io jobs to cores with fio options `cpus_allowed=0-` and `--cpus_allowed_policy=split` so I get 1 job per core. The kernel is configured with PREEMPT_NONE=y. Best regards, Andreas Hindborg