From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 1934E4600F for ; Tue, 7 Jan 2025 17:10:08 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id A041540BA4; Tue, 7 Jan 2025 17:10:07 +0100 (CET) Received: from mail-oa1-f54.google.com (mail-oa1-f54.google.com [209.85.160.54]) by mails.dpdk.org (Postfix) with ESMTP id 0F69E40676 for ; Tue, 7 Jan 2025 17:10:06 +0100 (CET) Received: by mail-oa1-f54.google.com with SMTP id 586e51a60fabf-29e5aedbebdso7268718fac.0 for ; Tue, 07 Jan 2025 08:10:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1736266205; x=1736871005; darn=dpdk.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=jv1nngvqPMK247in4eXjOA0KHWGeQPIAP77FUXt9ryY=; b=Ded3mCFzB7zGkRgn6QKOebQDbJmzF+fv1KQNql+SsyX0rmJm6Ew6gmBoMhJQfVN+YT fsNkUZPej0mZ02hIrzgNoBPUpNalyFN6kiRXabb0GmgBHDty+JtBOglM3fzYnqsP022x vV3CHHDfhSkUAcZM+1KCixAz7vSO/6pw/5NPaHteyqmgZ08l3BEX3iUdSKBFWwlVxfRM hOI9mY0nPzGgRYVfADCbcWMeU70U9HCznWrZV4t0wQpSaAWkUIKv2AEVzIsoz6Qlu2e1 bw3LkN2MnZWpbMQFuIa6lS0Ipj0PekJvOvLLOMKufINjKm1hMYZFENj5N+wmOuJeUulb tMSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736266205; x=1736871005; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=jv1nngvqPMK247in4eXjOA0KHWGeQPIAP77FUXt9ryY=; b=mrai88VkV/6uAxa5sVW55MK0BfCrfOrqC91KlKtE+LhXHKiFSGNgF2CCcE3hOICJqU WpLNYM0y/gAGWbPz5owqKq2N7PWyT/XzZ5a2Sf70yBX0BzASqhYDz7RNtFjSPgsQ/cqM BMAMnkNIbk6qarS7FYjS1NxI5hSkCqlPXxODr0/VI7k+9x+pHDzrIn0/bRAsSvj19Oop T1qycxw/rUP4xCWA4IIuoIiraVOcf+d1wZW5FR61qPzDKK5FBBuotZUrA47OQMpBoIzR P4WVRwH6Xe++h+4JD10vi4bsUXxp9UICW1RQ6fwAbcv3TBMzyOeD2jZ51BEq3w6yqTX3 S16A== X-Gm-Message-State: AOJu0Yzs45Ob/y3P3RZX2LjVCZyyCW1MqaPp6X3NMpUfuMrEdqPD9gfG FOTDnYH2eKivHdMkf8KVdgHM5IPVk9UqdOtS7k3cUHuSx2Lid/7xWgGfGQzfS6GAt347YPLH/lM k2N+epnduNTSey5dFt3nnyVv8Ges= X-Gm-Gg: ASbGncs31dMidQk1zVqgdcOPl+JdnguG/T6zxH+IZnX6s09+SFSexEolW8zwrMLjgka kENxuaA3Fcu0tZbdz+B/zloTMhdE5Y2Ci/hiQ X-Google-Smtp-Source: AGHT+IHjKg3NTct/hky1aOTv3K3zJndtPfVLigszoFV/i4Z2TgcW7rI6Ou1XbOa/7mxn2lk8v8GEo7s1SXFvYEngpxY= X-Received: by 2002:a05:6871:328c:b0:29d:c832:7ef6 with SMTP id 586e51a60fabf-2a7fb40f20emr33775022fac.39.1736266205121; Tue, 07 Jan 2025 08:10:05 -0800 (PST) MIME-Version: 1.0 References: <20250104214032.04eb6d25@sovereign> <20250105010148.1ef26333@sovereign> <20250106231038.59a6fc4e@sovereign> In-Reply-To: From: Alan Beadle Date: Tue, 7 Jan 2025 11:09:54 -0500 Message-ID: Subject: Re: Multiprocess App Problems with tx_burst To: Dmitry Kozlyuk Cc: users@dpdk.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org > I think I might have found an error in my library's heap allocator > which can result in duplicate references to copies of the same data > header, which are supposed to be different headers. This could explain > some of my problems if the above usage is correct. I will continue > investigating this possibility. One thing gives me doubt. My code > includes frequent checks of all refcounts, so if it was accessing > something with a refcount of 0 then it should detect that, and so far > it has not. I have confirmed that this was the cause. Somehow the zero refcount was not detected in my periodic checks. Everything seems to work ok now. In summary, here is what was happening. The heap allocator I was using inside of my library had a concurrency bug where in rare cases it would allocate the same buffer to multiple concurrent threads. This led to two indirect references to the same mbuf, and the false appearance that the same mbuf had been returned twice by the DPDK allocator while still in use. Concurrency is hard. Thank you for your patient help Dmitry. -Alan