{"id":550,"date":"2010-11-01T00:05:44","date_gmt":"2010-10-31T14:05:44","guid":{"rendered":"http:\/\/brnz.org\/hbr\/?p=550"},"modified":"2010-11-05T22:55:27","modified_gmt":"2010-11-05T12:55:27","slug":"frame-times-are-like-pancakes","status":"publish","type":"post","link":"https:\/\/brnz.org\/hbr\/?p=550","title":{"rendered":"Frame times are like pancakes"},"content":{"rendered":"

Time to generate image data, no DMA:<\/em> 0.015962s<\/p>\n

Time to generate data, with DMA to framebuffer:<\/em> 0.048529s. \u00a0That’s not good.<\/p>\n

Total amount of data transferred:<\/em> one 1080p frame — ~8MB.<\/p>\n

Measured average latency of 4*16KB DMA puts:<\/em> 577\u00b5s — ~1000 times slower than expected. \u00a0Something’s really not right.<\/p>\n

…<\/p>\n

Oh.<\/p>\n

First accesses to memory will be more expensive.<\/p>\n

Time to generate and DMA first frame:<\/em> 0.048529s<\/p>\n

Time to generate and DMA second frame:<\/em> 0.016370s<\/p>\n

Time to generate and DMA subsequent frames:<\/em> 0.015944s — slightly faster than with no DMA.<\/p>\n

There’s still plenty of work to be done before it’s functional and interesting, but I may yet hit my goal of 60 fps for this project :)<\/p>\n","protected":false},"excerpt":{"rendered":"

Time to generate image data, no DMA: 0.015962s Time to generate data, with DMA to framebuffer: 0.048529s. \u00a0That’s not good. Total amount of data transferred: one 1080p frame — ~8MB. Measured average latency of 4*16KB DMA puts: 577\u00b5s — ~1000 times slower than expected. \u00a0Something’s really not right. … Oh. First accesses to memory will … Continue reading “Frame times are like pancakes”<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[5,26,4],"tags":[36,34],"_links":{"self":[{"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=\/wp\/v2\/posts\/550"}],"collection":[{"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=550"}],"version-history":[{"count":10,"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=\/wp\/v2\/posts\/550\/revisions"}],"predecessor-version":[{"id":564,"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=\/wp\/v2\/posts\/550\/revisions\/564"}],"wp:attachment":[{"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=550"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=550"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/brnz.org\/hbr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=550"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}