From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Holger_Hoffst=c3=a4tte?= Subject: Re: [PATCH net] r8169: fix NAPI handling under high load Date: Tue, 16 Oct 2018 23:17:31 +0200 Message-ID: References: <8f84fe39-3d8d-396d-3b97-027e0a83f8cb@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "netdev@vger.kernel.org" To: Heiner Kallweit , David Miller , Realtek linux nic maintainers Return-path: Received: from mail02.iobjects.de ([188.40.134.68]:34440 "EHLO mail02.iobjects.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726067AbeJQFTv (ORCPT ); Wed, 17 Oct 2018 01:19:51 -0400 In-Reply-To: <8f84fe39-3d8d-396d-3b97-027e0a83f8cb@gmail.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 10/16/18 22:37, Heiner Kallweit wrote: > rtl_rx() and rtl_tx() are called only if the respective bits are set > in the interrupt status register. Under high load NAPI may not be > able to process all data (work_done == budget) and it will schedule > subsequent calls to the poll callback. > rtl_ack_events() however resets the bits in the interrupt status > register, therefore subsequent calls to rtl8169_poll() won't call > rtl_rx() and rtl_tx() - chip interrupts are still disabled. Very interesting! Could this be the reason for the mysterious hangs & resets we experienced when enabling BQL for r8169? They happened more often with TSO/GSO enabled and several people attempted to fix those hangs unsuccessfully; it was later reverted and has been since then (#87cda7cb43). If this bug has been there "forever" it might be tempting to re-apply BQL and see what happens. Any chance you could give that a try? I'll gladly test patches, just like I'll run this one. cheers Holger