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 AC3DB1F0E25 for ; Mon, 2 Mar 2026 04:41:55 +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=1772426515; cv=none; b=PL13kNNv5MW3sYbmywn19XRNP9QX+zzrZMkE8Dv0rChF0uEbJDzH5T3clTo+hsFX7qlYA5KQuzVit8mDrDu2+dCyKg0Xvr/9e4Er5EVLN4CdcJOcPOvDjfxHqwgMgfrdyzJ6TxAsW7q2Phm6QNwkCGQe14w6CVkICCdQcZ41yv8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772426515; c=relaxed/simple; bh=fcRYR4a6jxr3XgjMBW9vNFEZzI9xovqZAmyb7cbN3hA=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=Tffzr5j2u79RFVj2IniydlK3IuJyKgqOTn3wRQomsOLVXZuVeXzHgI6FWlDJi7z68V/OEz7j8JWyhxxKlY28FiFO95U2zJRlYo9m4Ng5yc6OG/kVWeGWRxpbkHQ0OmsZ9yp7uFGyy9BTrOCfq290sgGkBcHN7Zp0f1nRLhjU1B0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PHFRpsQn; 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="PHFRpsQn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5015C2BC86; Mon, 2 Mar 2026 04:41:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772426515; bh=fcRYR4a6jxr3XgjMBW9vNFEZzI9xovqZAmyb7cbN3hA=; h=Date:Subject:To:References:From:In-Reply-To:From; b=PHFRpsQnaWp36he3/jv6atLX6f5uuII7iOFtRgI2hkpmOcFhjRTEv/PxCUnuhWARi YX9uZmK1fKVyQjbJVsaSRfcWUzS6xS8fprWJFm19RrZ+BGuU/+fJGqI+gCywP1TsAA Ow/TKYIH6u+5A3fz/aGPU6g+2hmAxHpqV9wv86H5IIcG8xrIhehBVSvnwfTDl9PGrp LUUrJ1lAlzgLDv4BHbttyjQIsRoeqVRCghyNPxpokRoQgssVfTKgovNQEqoh8fNTDG Adw2vvxKn/a2BvPL8YSAMgBOOtgeGUMrWJraXUvMlBZIXSs1kVjeNaUKTqH+JTMLVc +QpfwL4oqwX8g== Message-ID: <1d1f28e2-cdb0-42a4-ae7a-eaaccac3647b@kernel.org> Date: Mon, 2 Mar 2026 13:36:28 +0900 Precedence: bulk X-Mailing-List: fio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/8] zbd: introduce write_zone_remainder option To: Shin'ichiro Kawasaki , fio@vger.kernel.org, Jens Axboe , Vincent Fu References: <20260302022609.3526823-1-shinichiro.kawasaki@wdc.com> <20260302022609.3526823-4-shinichiro.kawasaki@wdc.com> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <20260302022609.3526823-4-shinichiro.kawasaki@wdc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/2/26 11:26 AM, Shin'ichiro Kawasaki wrote: > When the specified block size is not aligned with the zone size or the > write pointer positions at workload start, write workloads create > unwritten remainder areas at the ends of zones. These remainder areas > leave zones in the open condition. This disrupts the intended write > target zone selection. > > Previous commits e1a1b59b0b9b ("zbd: finish zones with remainder smaller > than minimum write block size") and e2e29bf6f830 ("zbd: finish zone when > all random write target zones have small remainder") attempted to solve > this problem by issuing zone finish operation for zones with small > remainders. However, this approach caused performance degradation due to > two reasons. First, the zone finish operation requires substantial > execution time. Second, zone finish operation requires to wait for in- > flight writes from other jobs to complete, which is done by calling > io_u_quiesce() before the zone finish operation. > > To avoid the performance degradation, introduce the new option named > "write_zone_remainder". When the option is specified, issue writes to > the remainder areas instead of issuing zone finish operation. The write > operation makes the zones in the full condition in the same manner as > the zone finish operation, freeing up the zone resource of the device > and enabling writing to other zones. Also when the option is set, skip > the io_u_quiesce() which was required before the zone finish operation. > The performance benefit by eliminating the waits on in-flight writes are > particularly significant in asynchronous I/O workloads, where the write > operations to the remainder areas are managed as part of queued I/Os. > > The drawback of this approach is that writing these remainders requires > write sizes smaller than the minimum block size. As a result, when using > the write_zone_remainder option, the random map feature must be disabled > using the norandommap=1 option, which is automatically done when the > option is specified. > > Reviewed-by: Damien Le Moal > Signed-off-by: Shin'ichiro Kawasaki [...] > enum { > - FIO_SERVER_VER = 118, > + FIO_SERVER_VER = 119, Note: this change will conflict with my patches proposing the addition of the end_syncfs option. -- Damien Le Moal Western Digital Research