From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3689C352A3 for ; Tue, 11 Feb 2020 15:33:19 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 90B292082F for ; Tue, 11 Feb 2020 15:33:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 90B292082F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 233586EE87; Tue, 11 Feb 2020 15:33:19 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 590C46EE87 for ; Tue, 11 Feb 2020 15:33:17 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 20188949-1500050 for multiple; Tue, 11 Feb 2020 15:33:02 +0000 MIME-Version: 1.0 To: Mika Kuoppala , intel-gfx@lists.freedesktop.org From: Chris Wilson In-Reply-To: <87a75p9mhf.fsf@gaia.fi.intel.com> References: <20200210205722.794180-1-chris@chris-wilson.co.uk> <20200210205722.794180-3-chris@chris-wilson.co.uk> <87a75p9mhf.fsf@gaia.fi.intel.com> Message-ID: <158143518042.3635.5696176952305833936@skylake-alporthouse-com> User-Agent: alot/0.6 Date: Tue, 11 Feb 2020 15:33:00 +0000 Subject: Re: [Intel-gfx] [PATCH 3/7] drm/i915/selftests: Relax timeout for error-interrupt reset processing X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Quoting Mika Kuoppala (2020-02-11 15:23:24) > Chris Wilson writes: > > + /* Kick the tasklet to process the error */ > > + intel_engine_flush_submission(engine); > > This pattern of usage in selftests makes me want to add mb(); to > intel_engine_flush_submission(), as it does not seem to do it > implicitly. > > We want to flush submission and observe the effects, thus > it seems like a good place. Hmm. From the cpu perspective the memory barrier would be on the other side in clear_bit_unlock(), and flush_submission does unlock_wait. But, then, we have to factor in that we have to communicate with an external client the GPU, so perhaps an explicit memory barrier... We certainly do perform the memory barrier in order to set the GPU in motion, but have not relied on them for observing effects (aside from the CSB ringbuf). I don't see a strong argument that adding a 'mb/rmb' here will make any difference, I don't see what we are pairing with from the GPU perspective. But maybe there is? -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx