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<?xml-stylesheet type="text/xsl" href="https://community.arm.com/utility/feedstylesheets/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>Checking bandwidth boundness on Mali-T720</title><link>https://community.arm.com/developer/tools-software/graphics/f/discussions/48029/checking-bandwidth-boundness-on-mali-t720</link><description> I&amp;#39;m trying to infer if our application is bandwidth-bound (I believe it&amp;#39;s not the case) but I don&amp;#39;t have the read/write beat counters suggested in Tutorial . Although, I believe the ones I have already &amp;quot;resolve&amp;quot; the beats to the actual bytes value (</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: Checking bandwidth boundness on Mali-T720</title><link>https://community.arm.com/thread/168599?ContentTypeID=1</link><pubDate>Wed, 11 Nov 2020 15:08:35 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:b83f4079-cb2a-4654-9d2e-6e7762cb65fc</guid><dc:creator>JPJ</dc:creator><description>&lt;p&gt;Cheers Pete! Sadly, all the&amp;nbsp;&lt;span&gt;JobManager counters are also missing :/&amp;nbsp;for this particular device, but it sounds like it&amp;#39;s unlikely to be a problem.&lt;/span&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Checking bandwidth boundness on Mali-T720</title><link>https://community.arm.com/thread/168598?ContentTypeID=1</link><pubDate>Wed, 11 Nov 2020 15:01:53 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:42cd0d51-28ff-4a79-9de9-4d94fdef7389</guid><dc:creator>Peter Harris</dc:creator><description>&lt;p&gt;A proxy&amp;nbsp;stall rate, in the absence of GPU Active might be (e.g.):&lt;/p&gt;
&lt;p&gt;&lt;tt&gt;($MaliL2CacheExtReadsExternalBusStallsAR / max($MaliJobManagerCyclesJS0Cycles, $MaliJobManagerCyclesJS1Cycles)) * 100&lt;/tt&gt;&lt;/p&gt;
&lt;p&gt;2.6M stalls over 1 second doesn&amp;#39;t look like a problem though - assuming the GPU is 500MHz, that&amp;#39;s &amp;lt; 1% stall rate - so it looks happy.&lt;/p&gt;
&lt;p&gt;Cheers,&amp;nbsp;&lt;br /&gt;Pete&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Checking bandwidth boundness on Mali-T720</title><link>https://community.arm.com/thread/168597?ContentTypeID=1</link><pubDate>Wed, 11 Nov 2020 14:18:30 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:69cd02c4-e534-44ee-a21d-48dbc73cca4b</guid><dc:creator>JPJ</dc:creator><description>&lt;p&gt;Cheers Pete!&lt;br /&gt;Sadly, the GPU Active Cycles counter&amp;nbsp;has no data, i.e. always 0, in this device (Samsung J330F). I do get some stall related counters (image below) but I&amp;#39;m not sure if I can use them against anything else. This was measured over 1s btw.&lt;img alt=" " src="/resized-image/__size/600x240/__key/communityserver-discussions-components-files/13/T720_2D00_stalls.png" /&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Checking bandwidth boundness on Mali-T720</title><link>https://community.arm.com/thread/168594?ContentTypeID=1</link><pubDate>Wed, 11 Nov 2020 12:45:45 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:73bf7069-d2db-4ae8-8a94-1de0ede49ce3</guid><dc:creator>Peter Harris</dc:creator><description>&lt;p&gt;Hi JPJ,&amp;nbsp;&lt;/p&gt;
&lt;p&gt;For Midgard the capture will automatically covert beats into bytes, so you are correct that this has already been scaled.&amp;nbsp;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;A bandwidth of 740MB/s should be fine for a mobile system; in general GPU bandwidth measurements under 3GB/s&amp;nbsp;should be&amp;nbsp;fine even on an entry-level device.&amp;nbsp;&lt;br /&gt;&lt;br /&gt;The other thing you can check are the stall counters which the Midgard GPUs expose in addition to the bandwidth counters. Reviewing stalls as a percentage of GPU Active cycles is a good indicator of the memory system struggling. For normal content I&amp;#39;d expect to see stalls &amp;lt; 5% of the GPU Active cycles, although it is worth noting that stalls can happen for a number of reasons, not just high load (e.g. GPU clocked faster than the bus, so the GPU cannot use the bus every clock cycle).&lt;br /&gt;&lt;/span&gt;&lt;br /&gt;HTH,&amp;nbsp;&lt;br /&gt;Pete&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>