{"id":5406,"date":"2026-08-20T13:59:00","date_gmt":"2026-08-20T13:59:00","guid":{"rendered":"https:\/\/geekmungus.co.uk\/?p=5406"},"modified":"2026-08-20T13:59:00","modified_gmt":"2026-08-20T13:59:00","slug":"vmware-cpu-ready-time","status":"publish","type":"post","link":"https:\/\/geekmungus.co.uk\/?p=5406","title":{"rendered":"VMware CPU Ready Time"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">The CPU Ready Time shows how much time the VM is waiting to use the CPU on the VMware Host. Obviously you want this figure to be as low as possible, but typically below 10% is fine. The more you oversubscribe a host, the higher the CPU Ready Time because the VM(s) spend more time waiting to be scheduled onto a CPU. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A key thing to understand that just adding vCPU to your VM can make performance worse, the more vCPUs a VM has the harder it can be (during contention) for a hypervisor (VMware Host) to schedule the VM onto a pCPU.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">You can see the CPU Ready (and calculate it), by examining the CPU Ready Time metric on a VM, depending on the timeframes, you&#8217;ll need to consider different chart intervals.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"406\" src=\"https:\/\/geekmungus.co.uk\/wp-content\/uploads\/2026\/08\/image-1024x406.png\" alt=\"\" class=\"wp-image-5407\" srcset=\"https:\/\/geekmungus.co.uk\/wp-content\/uploads\/2026\/08\/image-1024x406.png 1024w, https:\/\/geekmungus.co.uk\/wp-content\/uploads\/2026\/08\/image-300x119.png 300w, https:\/\/geekmungus.co.uk\/wp-content\/uploads\/2026\/08\/image-768x304.png 768w, https:\/\/geekmungus.co.uk\/wp-content\/uploads\/2026\/08\/image-1536x609.png 1536w, https:\/\/geekmungus.co.uk\/wp-content\/uploads\/2026\/08\/image.png 1643w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">So in our case we&#8217;re at about 69ms CPU Ready Time, so let&#8217;s calculate that, depending on your graphs &#8220;period&#8221; setting, we&#8217;ll use one of the following Charter Intervals in our calculation.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Realtime: <strong>20 seconds<\/strong><\/li>\n\n\n\n<li>Past Day: 5 minutes <strong>(300 seconds)<\/strong><\/li>\n\n\n\n<li>Past Week: 30 minutes <strong>(1800 seconds)<\/strong><\/li>\n\n\n\n<li>Past Month: 2 hours <strong>(7200 seconds)<\/strong><\/li>\n\n\n\n<li>Past Year: 1 day <strong>(86400 seconds)<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">(CPU value (summation) \/ (Chart Interval in Seconds * 1000)) * 100 = % CPU ready<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So putting in our figures that becomes:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">(69 \/ (20 * 1000)) * 100 = 0.3% Ready<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So well under the 10%-ish threshold for potential performance problems to possibly appear. Its also worth noting that using a longer interval can give you better results for production systems over a longer period of time.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The CPU Ready Time shows how much time the VM is waiting to use the CPU on the VMware Host. Obviously you want this figure to be as low as possible, but typically below 10% is fine. The more you oversubscribe a host, the higher the CPU Ready Time because the VM(s) spend more time &#8230; <a title=\"VMware CPU Ready Time\" class=\"read-more\" href=\"https:\/\/geekmungus.co.uk\/?p=5406\" aria-label=\"Read more about VMware CPU Ready Time\">Read more<\/a><\/p>\n","protected":false},"author":4,"featured_media":4373,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[25],"tags":[],"class_list":["post-5406","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-vmware"],"_links":{"self":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/5406","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5406"}],"version-history":[{"count":1,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/5406\/revisions"}],"predecessor-version":[{"id":5408,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/5406\/revisions\/5408"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/media\/4373"}],"wp:attachment":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5406"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5406"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5406"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}