From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 65ED53A63FD for ; Wed, 21 Jan 2026 07:16:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768979818; cv=none; b=uIw5iFlyW98JUG/4rXDURSwKX1bc27ElDmKsIOfrpc9gq8uTeQSsSSDbJxohG//v+NIFkyl0m2XbhEFbJwYqdBjinqv7dDEEHF/RDCR96FQawaezn04TJsdJOcfjzLZHi33B0JwfniJA6IvjEns/5Q4k+4ZqPEo5MZx5aPSMMyI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768979818; c=relaxed/simple; bh=dMFLkkPsgdXoy/83+LrrIYtMFRMTMFScB3S/UYrfDyY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kLu6ktOhRhgjUW4d4kRC9js62v0FXhsrsknvO9syOauAA8Hz//lQVkbs9OHF0ZkaMXwFsE/OmfxgnVJDZZTe1auYlzUlfGxNKbIAGac5EucGeK9OfwvpAZ3WGDj3IcDAe1/FXfAIQRBxbFsHXHwRB6E6APASc3AZR3tSuXGX1Q4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 7BC86227AAA; Wed, 21 Jan 2026 08:16:53 +0100 (CET) Date: Wed, 21 Jan 2026 08:16:52 +0100 From: Christoph Hellwig To: Hans Holmberg Cc: linux-xfs@vger.kernel.org, Carlos Maiolino , Dave Chinner , "Darrick J . Wong" , Christoph Hellwig , dlemoal@kernel.org, johannes.thumshirn@wdc.com Subject: Re: [PATCH] xfs: always allocate the free zone with the lowest index Message-ID: <20260121071652.GB11963@lst.de> References: <20260120085746.29980-1-hans.holmberg@wdc.com> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260120085746.29980-1-hans.holmberg@wdc.com> User-Agent: Mutt/1.5.17 (2007-11-01) On Tue, Jan 20, 2026 at 09:57:46AM +0100, Hans Holmberg wrote: > Zones in the beginning of the address space are typically mapped to > higer bandwidth tracks on HDDs than those at the end of the address > space. So, in stead of allocating zones "round robin" across the whole > address space, always allocate the zone with the lowest index. > > This increases average write bandwidth for overwrite workloads > when less than the full capacity is being used. At ~50% utilization > this improves bandwidth for a random file overwrite benchmark > with 128MiB files and 256MiB zone capacity by 30%. > > Running the same benchmark with small 2-8 MiB files at 67% capacity > shows no significant difference in performance. Due to heavy > fragmentation the whole zone range is in use, greatly limiting the > number of free zones with high bw. Cool, thanks! Reviewed-by: Christoph Hellwig I always like patches that speed things up by removing code :)