{"id":46,"date":"2022-12-04T18:54:42","date_gmt":"2022-12-04T18:54:42","guid":{"rendered":"https:\/\/wp.hesling.com\/?p=46"},"modified":"2022-12-10T18:32:50","modified_gmt":"2022-12-10T18:32:50","slug":"qemu-storage-performance","status":"publish","type":"post","link":"http:\/\/wp.hesling.com\/?p=46","title":{"rendered":"QEMU Storage Performance"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Comparing the emulated SATA and VirtIO, the VirtIO disk comes out massively faster.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"2560\" height=\"1222\" src=\"https:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44.png\" alt=\"\" class=\"wp-image-49\" srcset=\"http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44.png 2560w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44-300x143.png 300w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44-1024x489.png 1024w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44-768x367.png 768w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44-1536x733.png 1536w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44-2048x978.png 2048w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44-1200x573.png 1200w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-04-13-54-44-1980x945.png 1980w\" sizes=\"auto, (max-width: 2560px) 100vw, 2560px\" \/><figcaption class=\"wp-element-caption\">Host machine is Debian on Intel Skylake with Samsung PM951 NVMe SSD.<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"788\" height=\"646\" src=\"https:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/image-1.png\" alt=\"\" class=\"wp-image-52\" srcset=\"http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/image-1.png 788w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/image-1-300x246.png 300w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/image-1-768x630.png 768w\" sizes=\"auto, (max-width: 788px) 100vw, 788px\" \/><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"wp-block-paragraph\">It looks like IO speed might be CPU latency bound, since setting the virtual disk caching mode to unsafe doesn&#8217;t really improve the performance by much.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"788\" height=\"645\" src=\"https:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-10-13-31-07.png\" alt=\"\" class=\"wp-image-72\" srcset=\"http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-10-13-31-07.png 788w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-10-13-31-07-300x246.png 300w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-10-13-31-07-768x629.png 768w\" sizes=\"auto, (max-width: 788px) 100vw, 788px\" \/><figcaption class=\"wp-element-caption\">With the virtio disk caching set to &#8220;unsafe&#8221;, where it ignores guest sync requests.<\/figcaption><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Reference Performance of the underlying Samsung PM951 NVMe<\/h2>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-08-12-37-42.png\" alt=\"\" class=\"wp-image-69\" width=\"611\" height=\"267\" srcset=\"http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-08-12-37-42.png 483w, http:\/\/wp.hesling.com\/wp-content\/uploads\/2022\/12\/Screenshot-from-2022-12-08-12-37-42-300x131.png 300w\" sizes=\"auto, (max-width: 611px) 100vw, 611px\" \/><figcaption class=\"wp-element-caption\"><a rel=\"noreferrer noopener\" href=\"https:\/\/www.samsung.com\/us\/labs\/pdfs\/collateral\/sm951-prodoverview-0615-v1.pdf\" target=\"_blank\">https:\/\/www.samsung.com\/us\/labs\/pdfs\/collateral\/sm951-prodoverview-0615-v1.pdf<\/a><\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Comparing the emulated SATA and VirtIO, the VirtIO disk comes out massively faster. It looks like IO speed might be CPU latency bound, since setting the virtual disk caching mode to unsafe doesn&#8217;t really improve the performance by much. Reference Performance of the underlying Samsung PM951 NVMe<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-46","post","type-post","status-publish","format-standard","hentry","category-notes"],"_links":{"self":[{"href":"http:\/\/wp.hesling.com\/index.php?rest_route=\/wp\/v2\/posts\/46","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wp.hesling.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wp.hesling.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wp.hesling.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/wp.hesling.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=46"}],"version-history":[{"count":8,"href":"http:\/\/wp.hesling.com\/index.php?rest_route=\/wp\/v2\/posts\/46\/revisions"}],"predecessor-version":[{"id":74,"href":"http:\/\/wp.hesling.com\/index.php?rest_route=\/wp\/v2\/posts\/46\/revisions\/74"}],"wp:attachment":[{"href":"http:\/\/wp.hesling.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=46"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wp.hesling.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=46"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wp.hesling.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=46"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}