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AJvYcCWxg7CNYMqvGLyHAtjnxYNAEQ2BPJigYCNCNjBzrh+D7mnkDh2wrQzqKSTg78vp+VJSW9j47H80JViO8sKq2HFIPsPmGTO0V34l34A= X-Gm-Message-State: AOJu0YzZGNrkTcJbSL22pofuNyF11Jwm6NPu+trSVvwWGNfd5aPxscfb r0GjxypAP7b43CXXDrZOjdumimbwkEjxrzYkX71dsrDPq/BMHr0VYDqN4j0l8mo= X-Google-Smtp-Source: AGHT+IElkL/zBCFHHaWiQ9kI38/vtt00gS40YnBc/B370nhydxYj7oNbKI27NQ4SuuKDpOrOGcNOuA== X-Received: by 2002:a17:90b:20b:b0:2cb:4382:99f1 with SMTP id 98e67ed59e1d1-2cd16191fcdmr555838a91.6.1721414198645; Fri, 19 Jul 2024 11:36:38 -0700 (PDT) Received: from [192.168.1.116] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2ccf7b2f300sm2025155a91.10.2024.07.19.11.36.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 19 Jul 2024 11:36:38 -0700 (PDT) Message-ID: Date: Fri, 19 Jul 2024 12:36:35 -0600 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC] Slow down of LTP tests aiodio_sparse.c and dio_sparse.c in kernel 6.6 To: Petr Vorel , ltp@lists.linux.it Cc: linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org, fstests@vger.kernel.org, Jan Kara , David Sterba , Filipe Manana , Amir Goldstein , Cyril Hrubis , Andrea Cervesato , Avinesh Kumar References: <20240719174325.GA775414@pevik> Content-Language: en-US From: Jens Axboe In-Reply-To: <20240719174325.GA775414@pevik> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/19/24 11:43 AM, Petr Vorel wrote: > Hi all, > > LTP AIO DIO tests aiodio_sparse.c [1] and dio_sparse.c [2] (using [3]) slowed > down on kernel 6.6 on Btrfs and XFS, when run with default parameters. These > tests create 100 MB sparse file and write zeros (using libaio or O_DIRECT) while > 16 other processes reads the buffer and check only zero is there. > > Runtime of this particular setup (i.e. 100 MB file) on Btrfs and XFS on the > same system slowed down 9x (6.5: ~1 min 6.6: ~9 min). Ext4 is not affected. > (Non default parameter creates much smaller file, thus the change is not that > obvious). > > Because the slowdown has been here for few kernel releases I suppose nobody > complained and the test is somehow artificial (nobody uses this in a real world). > But still it'd be good to double check the problem. I can bisect a particular > commit. > > Because 2 filesystems affected, could be "Improve asynchronous iomap DIO > performance" [4] block layer change somehow related? No, because that got disabled before release for unrelated reasons. Why don't you just bisect it, since you have a simple test case? -- Jens Axboe