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 BC5A584A35 for ; Sun, 21 Dec 2025 19:10:48 +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=1766344248; cv=none; b=TYrno6Mb2p9aZi0vS+X/Hoxw/YxZdHnkTmTP5SnY//AN18cxYTrsyjFJa67r5RTZZSUkm6CJbEdi5ElmSyU3LyRo3yUKnFRBes0Gtq3OmNs0Elw+iNLsjWnxGxaHi4MXUZqNdUdUoDUyFT3kSzZ4VDXMU+WbLKbsiaLzOOHKbVU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766344248; c=relaxed/simple; bh=LaVhOMWhtuYN1fezEcuVNN8oMKik5OXUko7VJ8drc68=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=UzfvLuvoWPpOcIOFc7k58oMyAh/O/7WF6LNWELwAFzwJVf4yAg2Ug5Vjn5UAs9MXz5ywUphgIIoKrzE1hgtaJeE/mBFwRIxYggzlzNrSyIA7z2txXsQ4uwznpOkRsG2imeeK9kiChPp+Fr2JDB/gGCt6b72v85G42WnfUMfHwys= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Yq57DdBA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Yq57DdBA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF472C4CEFB; Sun, 21 Dec 2025 19:10:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1766344248; bh=LaVhOMWhtuYN1fezEcuVNN8oMKik5OXUko7VJ8drc68=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Yq57DdBAi7v0gpvUqXGPg/UDr65/zIpjbf3FDG76RS3ftJtMGJFFtlPVmTrKH3lN1 e8/7YYoC0fNmZtYsH2+zEZCOPInSqRGrkeedPt+k8x5VOHfsvYNN1wyUB3ku+JYEVW QE0iyPK7n7+YshSqyoK1V4rQFhSHEVU+11oelqLM= Date: Sun, 21 Dec 2025 11:10:47 -0800 From: Andrew Morton To: Wangyang Guo Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, Tianyou Li , Tim Chen , Dan Liang Subject: Re: [PATCH] lib/group_cpus: make group CPU cluster aware Message-Id: <20251221111047.597248db9868d278c7786f6b@linux-foundation.org> In-Reply-To: <20251024023038.872616-1-wangyang.guo@intel.com> References: <20251024023038.872616-1-wangyang.guo@intel.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Fri, 24 Oct 2025 10:30:38 +0800 Wangyang Guo wrote: > As CPU core counts increase, the number of NVMe IRQs may be smaller than > the total number of CPUs. This forces multiple CPUs to share the same > IRQ. If the IRQ affinity and the CPU’s cluster do not align, a > performance penalty can be observed on some platforms. It would be helpful to quantify "performance penalty". At least give readers some approximate understanding of how serious this issue is, please. > This patch improves IRQ affinity by grouping CPUs by cluster within each > NUMA domain, ensuring better locality between CPUs and their assigned > NVMe IRQs. > > Reviewed-by: Tianyou Li > Reviewed-by: Tim Chen > Tested-by: Dan Liang > Signed-off-by: Wangyang Guo Patch hasn't attracted additional review so I'll queue this version for some testing in mm.git's mm-nonmm-unstable branch. I'll add a note-to-self that a changelog addition is desirable. Thanks.