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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 8CBA3C433DB for ; Mon, 1 Feb 2021 13:24:08 +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 1B32164DFA for ; Mon, 1 Feb 2021 13:24:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B32164DFA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1924D6E084; Mon, 1 Feb 2021 13:24:07 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id B9ADD6E084 for ; Mon, 1 Feb 2021 13:24:05 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B07211042; Mon, 1 Feb 2021 05:24:04 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CAEA23F66E; Mon, 1 Feb 2021 05:24:03 -0800 (PST) Subject: Re: [PATCH 3/3] drm/panfrost: Stay in the threaded MMU IRQ handler until we've handled all IRQs To: Boris Brezillon References: <20210201082116.267208-1-boris.brezillon@collabora.com> <20210201082116.267208-4-boris.brezillon@collabora.com> <20210201135902.6798a203@collabora.com> From: Steven Price Message-ID: Date: Mon, 1 Feb 2021 13:24:00 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210201135902.6798a203@collabora.com> Content-Language: en-GB X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org, Rob Herring , Robin Murphy , Alyssa Rosenzweig Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 01/02/2021 12:59, Boris Brezillon wrote: > On Mon, 1 Feb 2021 12:13:49 +0000 > Steven Price wrote: > >> On 01/02/2021 08:21, Boris Brezillon wrote: >>> Doing a hw-irq -> threaded-irq round-trip is counter-productive, stay >>> in the threaded irq handler as long as we can. >>> >>> Signed-off-by: Boris Brezillon >> >> Looks fine to me, but I'm interested to know if you actually saw a >> performance improvement. Back-to-back MMU faults should (hopefully) be >> fairly uncommon. > > I actually didn't check the perf improvement or the actual number of > back-to-back MMU faults, but > dEQP-GLES31.functional.draw_indirect.compute_interop.large.drawelements_combined_grid_1000x1000_drawcount_5000 > seemed to generate a few of those, so I thought it'd be good to > optimize that case given how trivial it is. Fair enough! I was just a little concerned that Panfrost was somehow provoking enough interrupts that this was a measurable performance improvement. I assume you'll push these to drm-misc-next (/fixes) as appropriate. Thanks, Steve >> >> Regardless: >> >> Reviewed-by: Steven Price >> >>> --- >>> drivers/gpu/drm/panfrost/panfrost_mmu.c | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c >>> index 21e552d1ac71..65bc20628c4e 100644 >>> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c >>> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c >>> @@ -580,6 +580,8 @@ static irqreturn_t panfrost_mmu_irq_handler_thread(int irq, void *data) >>> u32 status = mmu_read(pfdev, MMU_INT_RAWSTAT); >>> int i, ret; >>> >>> +again: >>> + >>> for (i = 0; status; i++) { >>> u32 mask = BIT(i) | BIT(i + 16); >>> u64 addr; >>> @@ -628,6 +630,11 @@ static irqreturn_t panfrost_mmu_irq_handler_thread(int irq, void *data) >>> status &= ~mask; >>> } >>> >>> + /* If we received new MMU interrupts, process them before returning. */ >>> + status = mmu_read(pfdev, MMU_INT_RAWSTAT); >>> + if (status) >>> + goto again; >>> + >>> mmu_write(pfdev, MMU_INT_MASK, ~0); >>> return IRQ_HANDLED; >>> }; >>> >> > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel