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=2.7 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 B27A6C433E0 for ; Mon, 25 May 2020 22:07:53 +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 7DA9A2075F for ; Mon, 25 May 2020 22:07:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TZJUWGYp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7DA9A2075F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=amd-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4647F89722; Mon, 25 May 2020 22:07:53 +0000 (UTC) Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by gabe.freedesktop.org (Postfix) with ESMTPS id E6286893ED for ; Mon, 25 May 2020 22:07:51 +0000 (UTC) Received: by mail-pg1-x536.google.com with SMTP id u5so9116757pgn.5 for ; Mon, 25 May 2020 15:07:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=aT4CaCQd/M/aLFVh90rAWA/xL3wGxZzYCGYut4HhGAs=; b=TZJUWGYpOkeOkb3wKX5LFONa1QWZL8u8lQsieQMHsuuilhpgVIelTYv45KDwm7Enqb UV94Gjrb7shm6CwMrn8fL2ycWHyk0w3gxNzYZ3CoxAxrG6KJxNHUV/jeDc+R7HvNTVj5 Ro/buGas0eSttWysNAl8sA5+Nb7lrpZ1gsV+mTeRaHbKqzCeRBz/hkYGGJg9+WmurPxz wZHcvfYuUJlecNM177wqVNQ5R+8HHKjUheRdenBD7iCb56QgtKD+Y8oPxYhHYLOQ1sjK 4CgzUm/peXSlEsgN7o52sTcyu9cK+C6fXo5389TEI6rYBuzAg7phoTLEB5yV46NLUfPA R7PA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=aT4CaCQd/M/aLFVh90rAWA/xL3wGxZzYCGYut4HhGAs=; b=gJ47x4LqMb62TWoSu7//iQ0aXJ+4aNzObrcshlh/7TUS9RiALeKYqbY2giQMHnz6NO 8QBJ8tqQqVgq5EjE0NxG3Pwl8xkrmTiS3gID6JWStAmsPiz9PnfhdTiqcluC301fe3md mx74xpPwwrhKBesUApZWk36bY6uQTSxgk9ydPMl2wT8j2ILqmJVZdKtWab9BQW605PpW xDs3T67RHCRwdGZkc4JKXp7t93Od0CS/4GQWrVjOzyND6K+AOhEfYDIAO63Jcw+UIg3a pz74/rmPP5QiDMSfRGfhnRvCJ8OTaDoIV+7c7wQQzMXhC0eZuJWcM0CeoU3Ei3PDYyKm LayA== X-Gm-Message-State: AOAM530lkwXmrNbocAuHOjIoClPKFSnKSi80IeUz+kCa4HBJRMoW0etR pwKbtWyZwpCP4lSbIuPwQTv/AwWeHfJmNxHSCHgTE741 X-Google-Smtp-Source: ABdhPJw6xPkc60k2r3IKUR4E/qdgaVWxsi4bbms2XQYTowYMvlcd0y5cc0rjL4QEdOb5TUzj9XzBVDbSyhobJ51wvOg= X-Received: by 2002:a65:5bc5:: with SMTP id o5mr22593934pgr.233.1590444471380; Mon, 25 May 2020 15:07:51 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: =?UTF-8?B?TWFyZWsgT2zFocOhaw==?= Date: Mon, 25 May 2020 18:07:14 -0400 Message-ID: Subject: Re: amdgpu doesn't do implicit sync, requires drivers to do it in IBs To: amd-gfx mailing list , Bas Nieuwenhuizen , =?UTF-8?Q?Michel_D=C3=A4nzer?= , =?UTF-8?Q?Christian_K=C3=B6nig?= X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============1394669348==" Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" --===============1394669348== Content-Type: multipart/alternative; boundary="000000000000c06f2a05a6803583" --000000000000c06f2a05a6803583 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable If a user mode driver is changed to rely on the existence of implicit sync, it results in corruption and flickering as reported here: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2950 Marek On Mon, May 25, 2020 at 6:05 PM Marek Ol=C5=A1=C3=A1k wr= ote: > Hi Christian, > > Bas and Michel wanted to discuss this. The main disadvantage of no > implicit (pipeline) sync within the same queue is that we get lower > performance and lower GPU utilization in some cases. > > We actually never really needed the kernel to have implicit sync, because > all user mode drivers contained hacks to work without it. > > Marek > --000000000000c06f2a05a6803583 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
If a user mode driver is changed to rely on the exist= ence of implicit sync, it results in corruption and flickering as reported = here: ht= tps://gitlab.freedesktop.org/mesa/mesa/-/issues/2950

Marek

On Mon, May 25, 2020 at 6:05 PM Marek Ol=C5=A1=C3=A1k= <maraeo@gmail.com> wrote:
<= div>Hi Christian,

Bas and Michel wanted to discuss= this. The main disadvantage of no implicit (pipeline) sync within the same= queue is that we get lower performance and lower GPU utilization in some c= ases.

We actually never really needed the kern= el to have implicit sync, because all user mode drivers contained hacks to = work without it.

Marek
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