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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 545C6C433F5 for ; Wed, 19 Jan 2022 16:15:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354199AbiASQP5 (ORCPT ); Wed, 19 Jan 2022 11:15:57 -0500 Received: from outbound1a.eu.mailhop.org ([52.58.109.202]:27588 "EHLO outbound1a.eu.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346196AbiASQPz (ORCPT ); Wed, 19 Jan 2022 11:15:55 -0500 ARC-Seal: i=1; a=rsa-sha256; t=1642608952; cv=none; d=outbound.mailhop.org; s=arc-outbound20181012; b=kxC1WkaeocxOKFARM9ByXViqcVSKvTabcCDr4GkmmWh+KoePfqjGC1TTdYIyG+To3KM90FO9nU5Fa WlgBobjn/449O//6+Uptcg176qgS38tplmAdna5bscD4XDxwWxoQw0NrHbXi0M+TNBAPrEvilwWHn/ iIAPp63HzTv9RdZc6u2Ek89LRUlfiD+/92tVXNAenAy5dvp/ieb/iySM7zSffbaYF9iaspIC32pU3Y ArmO0Yg/c773Ta/4KLHW1LCBZKc9/wd10sESTdfO3QmOnk8SGcnzukVDLGin4Rg5Sbr/MGFzHQL9ly y5AT1v2GoVKAW8Z2QPje0uKE/KqsUUg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=arc-outbound20181012; h=content-type:mime-version:message-id:in-reply-to:date:references:subject:cc: to:from:dkim-signature:dkim-signature:from; bh=VQkws5cfDXUAVloFG/KiXRI6miR49pWBsef8Tqe52gE=; b=DROucEpWMAWSNzreneKr2Wz/6RktSjothuyxVhBgglmkQDlPGbCp71wAK6+oz5diROqQGswUAKT5m g/M4NdoWG8iM7Fttgt2BugwZji6DRpvSNNx88Cx+sals5DtpDZpVzUIlDyOz7Te6jld5rpIEPqfAGo 94ZmaoMff//l8NCDcC6SIQlP6lNh2q30MKOXyoTVyzwyb65EdwrhyBHO26DScc1mKU+YkTM0ivHGZ2 pcY+g3AlmpFTfk0l8xHLP7e4TU120aemRVRz6hGURThae6EKkOjmdYW4dFThUsmchYJ258jfSyxpxP LyB33MK6NNz4gnMhgzdeSHNqLYT0MLQ== ARC-Authentication-Results: i=1; outbound2.eu.mailhop.org; spf=pass smtp.mailfrom=stackframe.org smtp.remote-ip=91.207.61.48; dmarc=none header.from=stackframe.org; arc=none header.oldest-pass=0; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stackframe.org; s=duo-1634547266507-560c42ae; h=content-type:mime-version:message-id:in-reply-to:date:references:subject:cc: to:from:from; bh=VQkws5cfDXUAVloFG/KiXRI6miR49pWBsef8Tqe52gE=; b=TToPtR0bHKToDxiw8UMDGv10xrkXW8uyXFRYgxY5Mhkw4EsVhsQD4dK9xGYuzQRc1N8MKa8o8+BLr axYeMiqDMaIXozAFfQ7f/OA9CMgsERMBk/O4AH8dD+RqYujBUhK/u2s2pNPDx5QZN3VI6tOXU8uz8F vbS5DUXV0PsSM8Jo= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=dkim-high; h=content-type:mime-version:message-id:in-reply-to:date:references:subject:cc: to:from:from; bh=VQkws5cfDXUAVloFG/KiXRI6miR49pWBsef8Tqe52gE=; b=E0YaHv4GxVcZCjbY0tPAynCkZWuJgL947/czeFAJpN4/sK4xGesGsghce17+LLzjEOE8Lfd4PvU9D DBoxb7YuiSl4UjjzmEoG0wrYwZyIEgP5OSQYOHeniikKx4yJdqxhlDvKnTzxKUUekYkl2Burd6Oige c4MOegAiQeblQWiIsryC5qlvDQdrunVMF3be5dRC1McNCqwWyqSvazmL5I2DpBaPWOjwjVTOrcoehC zAewZqvn1/fNdp6d/5gTxH3dmYBdc7Xr1cuwOFE1UA/+LZAUgVSA3ngkdmjkzsqn6qL8yHNabTIQyj 7sk2GAf9sV7gqPCQsowAsOyigxh2GZg== X-Originating-IP: 91.207.61.48 X-MHO-RoutePath: dG9ta2lzdG5lcm51 X-MHO-User: 0f13a236-7943-11ec-a077-973b52397bcb X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Mail-Handler: DuoCircle Outbound SMTP Received: from mail.duncanthrax.net (propper.duncanthrax.net [91.207.61.48]) by outbound2.eu.mailhop.org (Halon) with ESMTPSA id 0f13a236-7943-11ec-a077-973b52397bcb; Wed, 19 Jan 2022 16:15:47 +0000 (UTC) Received: from hsi-kbw-109-193-149-228.hsi7.kabel-badenwuerttemberg.de ([109.193.149.228] helo=x1.stackframe.org.stackframe.org) by mail.duncanthrax.net with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nADcf-0059VO-M4; Wed, 19 Jan 2022 18:15:45 +0200 From: Sven Schnelle To: Daniel Vetter Cc: Helge Deller , linux-fbdev@vger.kernel.org, Geert Uytterhoeven , dri-devel@lists.freedesktop.org, Thomas Zimmermann , Hamza Mahfooz Subject: Re: fbdev: Garbage collect fbdev scrolling acceleration References: <87zgnz71ic.fsf@x1.stackframe.org> Date: Wed, 19 Jan 2022 17:15:44 +0100 In-Reply-To: (Daniel Vetter's message of "Wed, 19 Jan 2022 16:39:03 +0100") Message-ID: <87y23bitvz.fsf@x1.stackframe.org> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Hi Daniel, Daniel Vetter writes: > On Thu, Jan 13, 2022 at 10:46:03PM +0100, Sven Schnelle wrote: >> Helge Deller writes: >> > Maybe on fast new x86 boxes the performance difference isn't huge, >> > but for all old systems, or when emulated in qemu, this makes >> > a big difference. >> > >> > Helge >> >> I second that. For most people, the framebuffer isn't important as >> they're mostly interested in getting to X11/wayland as fast as possible. >> But for systems like servers without X11 it's nice to have a fast >> console. > > Fast console howto: > - shadow buffer in cached memory > - timer based upload of changed areas to the real framebuffer > > This one is actually fast, instead of trying to use hw bltcopy and having > the most terrible fallback path if that's gone. Yes drm fbdev helpers has > this (but not enabled on most drivers because very, very few people care). Hmm.... Take my Laptop with a 4k (3180x2160) screen as an example: Lets say on average the half of every line is filled with text. So 3840/2*2160 pixels that change = 4147200 pixels. Every pixel takes 4 bytes = 16,588800 bytes per timer interrupt. In another Mail updating on vsync was mentioned, so multiply that by 60 and get ~927MB. And even if you only update the screen ony 4 times per second, that would be ~64MB of data. I'm likely missing something here. 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 69EFEC433F5 for ; Wed, 19 Jan 2022 16:16:58 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C1F9810E344; Wed, 19 Jan 2022 16:16:57 +0000 (UTC) X-Greylist: delayed 163685 seconds by postgrey-1.36 at gabe; Wed, 19 Jan 2022 16:16:56 UTC Received: from outbound5f.eu.mailhop.org (outbound5f.eu.mailhop.org [3.127.8.113]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0FA9B10E334 for ; Wed, 19 Jan 2022 16:16:55 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; t=1642608951; cv=none; d=outbound.mailhop.org; s=arc-outbound20181012; b=lNGJ+U/AFaDAlxjJxWt6BMcFLrXT9YP3qjCW0+uXil0tUgN1+ZGxX6h2UNsxjRnS1Ir7V0QR2IqKt EUwW5YC8irEVGfEQilP5/MIyddlZjexGq+79UV0KBbqEFsTiPRQHOPz2wrnaafqOksJPqStIh4gsSP UQGYJuGOu4aG0jV+RkzqnkZRjRRWrD+LXVPRYW/tOZKPPa2rbpjBEBPseGo9QG0Hty3Yepedn80PCM /S00A+Duo6nX1efpLXNDr8CaItddJ0X9zkdMaUXasUlzBhiCrDBkUvGBz6UyuCPFho8GocKo0Qqp1P iVJTZKslF3UEVTw2Gtxzmuce7TcIrSQ== ARC-Message-Signature: i=1; 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Wed, 19 Jan 2022 16:15:47 +0000 (UTC) Received: from hsi-kbw-109-193-149-228.hsi7.kabel-badenwuerttemberg.de ([109.193.149.228] helo=x1.stackframe.org.stackframe.org) by mail.duncanthrax.net with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nADcf-0059VO-M4; Wed, 19 Jan 2022 18:15:45 +0200 From: Sven Schnelle To: Daniel Vetter Subject: Re: fbdev: Garbage collect fbdev scrolling acceleration References: <87zgnz71ic.fsf@x1.stackframe.org> Date: Wed, 19 Jan 2022 17:15:44 +0100 In-Reply-To: (Daniel Vetter's message of "Wed, 19 Jan 2022 16:39:03 +0100") Message-ID: <87y23bitvz.fsf@x1.stackframe.org> MIME-Version: 1.0 Content-Type: text/plain 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: linux-fbdev@vger.kernel.org, Hamza Mahfooz , Helge Deller , dri-devel@lists.freedesktop.org, Geert Uytterhoeven , Thomas Zimmermann Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Daniel, Daniel Vetter writes: > On Thu, Jan 13, 2022 at 10:46:03PM +0100, Sven Schnelle wrote: >> Helge Deller writes: >> > Maybe on fast new x86 boxes the performance difference isn't huge, >> > but for all old systems, or when emulated in qemu, this makes >> > a big difference. >> > >> > Helge >> >> I second that. For most people, the framebuffer isn't important as >> they're mostly interested in getting to X11/wayland as fast as possible. >> But for systems like servers without X11 it's nice to have a fast >> console. > > Fast console howto: > - shadow buffer in cached memory > - timer based upload of changed areas to the real framebuffer > > This one is actually fast, instead of trying to use hw bltcopy and having > the most terrible fallback path if that's gone. Yes drm fbdev helpers has > this (but not enabled on most drivers because very, very few people care). Hmm.... Take my Laptop with a 4k (3180x2160) screen as an example: Lets say on average the half of every line is filled with text. So 3840/2*2160 pixels that change = 4147200 pixels. Every pixel takes 4 bytes = 16,588800 bytes per timer interrupt. In another Mail updating on vsync was mentioned, so multiply that by 60 and get ~927MB. And even if you only update the screen ony 4 times per second, that would be ~64MB of data. I'm likely missing something here.