<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta name="Generator" content="Microsoft Word 15 (filtered medium)"> <style></style> </head> <body lang="EN-US" link="blue" vlink="purple"> <div class="WordSection1"> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#2F5496">Agreed.<o:p></o:p></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#2F5496"><o:p> </o:p></span></p> <p class="MsoNormal">>I think that the consensus with Alex and me is that we should avoid exactly that.<br> Christian, Alex’s concern is about ping-pong, not about the preferred domain. <br> <br> <span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#2F5496"><o:p></o:p></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#2F5496">Regards,<o:p></o:p></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#2F5496">Samuel Li<o:p></o:p></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#2F5496"><o:p> </o:p></span></p> <div style="border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt"> <div> <div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in"> <p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Marek Olšák [mailto:maraeo@gmail.com] <br> <b>Sent:</b> Monday, March 19, 2018 3:39 PM<br> <b>To:</b> Koenig, Christian <Christian.Koenig@amd.com><br> <b>Cc:</b> Li, Samuel <Samuel.Li@amd.com>; Michel Dänzer <michel@daenzer.net>; Alex Deucher <alexdeucher@gmail.com>; amd-gfx list <amd-gfx@lists.freedesktop.org><br> <b>Subject:</b> Re: [PATCH 1/2] drm/amdgpu: Enable scatter gather display support<o:p></o:p></span></p> </div> </div> <p class="MsoNormal"><o:p> </o:p></p> <div> <div> <div> <p class="MsoNormal">On Mon, Mar 19, 2018 at 3:27 PM, Christian König <<a href="mailto:christian.koenig@amd.com" target="_blank">christian.koenig@amd.com</a>> wrote:<o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal">I think that the consensus with Alex and me is that we should avoid exactly that.<br> <br> Overriding the preferred domain in the kernel is a no-go for that patch set, so please implement the discussed changes in Mesa.<o:p></o:p></p> </blockquote> <div> <p class="MsoNormal"><o:p> </o:p></p> </div> <div> <p class="MsoNormal">I don't see how Mesa can make a smarter decision than the kernel. If you overwrite the preferred domain of the buffer in the kernel, there will be no ping-ponging between domains. Mesa never changes the initial preferred domain.<o:p></o:p></p> </div> <div> <p class="MsoNormal"><o:p> </o:p></p> </div> <div> <p class="MsoNormal">Marek<o:p></o:p></p> </div> <div> <p class="MsoNormal"><o:p> </o:p></p> </div> <div> <p class="MsoNormal"> <o:p></o:p></p> </div> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal"><br> Regards,<br> Christian.<o:p></o:p></p> <div> <div> <p class="MsoNormal"><br> <br> Am 19.03.2018 um 20:22 schrieb Li, Samuel:<o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal" style="margin-bottom:12.0pt">I agree with Marek/Michel: since kernel sets the domain before scanning out, it shall update the preferred domain here too.<br> <br> Regards,<br> Samuel Li<br> <br> <o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal">-----Original Message-----<br> From: Koenig, Christian<br> Sent: Thursday, March 08, 2018 4:07 AM<br> To: Michel Dänzer <<a href="mailto:michel@daenzer.net" target="_blank">michel@daenzer.net</a>>; Li, Samuel<br> <<a href="mailto:Samuel.Li@amd.com" target="_blank">Samuel.Li@amd.com</a>>; Alex Deucher <<a href="mailto:alexdeucher@gmail.com" target="_blank">alexdeucher@gmail.com</a>><br> Cc: amd-gfx list <<a href="mailto:amd-gfx@lists.freedesktop.org" target="_blank">amd-gfx@lists.freedesktop.org</a>><br> Subject: Re: [PATCH 1/2] drm/amdgpu: Enable scatter gather display support<br> <br> Am 08.03.2018 um 09:35 schrieb Michel Dänzer:<o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal">On 2018-03-07 10:47 AM, Christian König wrote:<o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal">Am 07.03.2018 um 09:42 schrieb Michel Dänzer:<o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal" style="margin-bottom:12.0pt">On 2018-03-06 07:23 PM, Christian König wrote:<o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal">E.g. the last time I tested it placing things into GTT still<br> resulted in quite a performance penalty for rendering.<o:p></o:p></p> </blockquote> <p class="MsoNormal">FWIW, I think the penalty is most likely IOMMU related. Last time I<br> tested, I couldn't measure a big difference with IOMMU disabled.<o:p></o:p></p> </blockquote> <p class="MsoNormal">No, the penalty I'm talking about came from the ping/pong we did with<br> the scanout buffers.<br> <br> See when I tested this the DDX and Mesa where unmodified, so both<br> still assumed VRAM as placement for scanout BOs, but the kernel<br> forced scanout BOs into GTT for testing.<br> <br> So what happened was that on scanout we moved the VRAM BO to GTT<o:p></o:p></p> </blockquote> </blockquote> <p class="MsoNormal">and<o:p></o:p></p> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <p class="MsoNormal">after unpinning it on the first command submission which used the BO<br> we moved it back to VRAM again.<o:p></o:p></p> </blockquote> <p class="MsoNormal">In the meantime, I've had the same idea as Marek: Can't the kernel<br> driver simply change the BO's preferred domain to GTT when scanning<br> out from it? Then it won't move back to VRAM.<o:p></o:p></p> </blockquote> <p class="MsoNormal">Yes, I've considered this as well.<br> <br> But I think making the decision in Mesa is the cleaner approach.<br> <br> E.g. so far we only override the placement decision of userspace for two<br> reasons:<br> 1. We where running out of memory in VRAM.<br> 2. We have a hardware restriction which makes VRAM usage mandatory.<br> <br> And even then we never adjust the placement permanently, we just<br> temporary moved the buffer where it was needed and moved it back after<br> the operation completed.<br> <br> Additional to that Mesa might want to set even more flags and/or changes<br> it's behavior. E.g. use a tilling mode which both importer and export in an<br> A+A laptop understands etc...<br> <br> Regards,<br> Christian.<o:p></o:p></p> </blockquote> </blockquote> <p class="MsoNormal"><br> _______________________________________________<br> amd-gfx mailing list<br> <a href="mailto:amd-gfx@lists.freedesktop.org" target="_blank">amd-gfx@lists.freedesktop.org</a><br> <a href="https://lists.freedesktop.org/mailman/listinfo/amd-gfx" target="_blank">https://lists.freedesktop.org/mailman/listinfo/amd-gfx</a><o:p></o:p></p> </div> </div> </blockquote> </div> <p class="MsoNormal"><o:p> </o:p></p> </div> </div> </div> </div> </body> </html>