{"id":2433,"date":"2022-04-19T15:30:34","date_gmt":"2022-04-19T15:30:34","guid":{"rendered":"https:\/\/loadfocus.com\/blog\/?p=2433"},"modified":"2023-09-03T14:09:47","modified_gmt":"2023-09-03T14:09:47","slug":"what-is-cpu-utilization-in-performance-testing","status":"publish","type":"post","link":"https:\/\/loadfocus.com\/blog\/2022\/04\/what-is-cpu-utilization-in-performance-testing","title":{"rendered":"What is CPU Utilization in Performance Testing?"},"content":{"rendered":"<span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\"><\/span> <span class=\"rt-time\"> 2<\/span> <span class=\"rt-label rt-postfix\">minutes read<\/span><\/span><!-- pn-tldr --><h2>Key takeaways<\/h2><ul><li>CPU utilisation shows whether the server is working or waiting, which changes the diagnosis.<\/li><li>High CPU with low throughput usually means inefficient code, not insufficient hardware.<\/li><li>Watch it on the load generator too, since a saturated generator caps the test.<\/li><\/ul><!-- \/pn-tldr -->\n<p class=\"lead\"><strong>CPU<\/strong> or C<strong>entral Processing Unit<\/strong> is the brain of any computer and its main responsibility is processing all the tasks required by the running applications.<\/p>\n\n\n\n<p><strong>CPU Utilization<\/strong> is a key metric in performance testing which measures the percentage of time the CPU spends executing a task.<\/p>\n\n\n\n<p>One of the most crucial tasks to do when running a performance test is to monitor the resource utilization. There are four key areas to keep an eye on:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>CPU (Central Processing Unit)<\/li><li>Memory<\/li><li>Disk<\/li><li>Network<\/li><\/ul>\n\n\n\n<p>Actual CPU utilization may vary since certain tasks may require a heavier CPU time while others require less due to non-CPU resource requirements.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Does CPU Usage Mean?<\/h2>\n\n\n\n<p>CPU percent utilization represents how much of the total CPU&#8217;s processing power is currently being utilized.<\/p>\n\n\n\n<p>The CPU usage may increase with running performance tests with a higher number of virtual concurrent users.<\/p>\n\n\n\n<p>There are requests that can be handled easily with the CPU usage between 1% and 5%, and other heavier requests with CPU utilization between 80%-100%.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-style-default\"><a href=\"https:\/\/loadfocus.com\"><img loading=\"lazy\" decoding=\"async\" width=\"870\" height=\"360\" src=\"https:\/\/loadfocus.com\/blog\/wp-content\/uploads\/sign-up.jpeg\" alt=\"\" class=\"wp-image-2301\" srcset=\"https:\/\/loadfocus.com\/blog\/wp-content\/uploads\/sign-up.jpeg 870w, https:\/\/loadfocus.com\/blog\/wp-content\/uploads\/sign-up-800x331.jpeg 800w, https:\/\/loadfocus.com\/blog\/wp-content\/uploads\/sign-up-600x248.jpeg 600w, https:\/\/loadfocus.com\/blog\/wp-content\/uploads\/sign-up-768x318.jpeg 768w\" sizes=\"auto, (max-width: 870px) 100vw, 870px\" \/><\/a><figcaption>Cloud Testing Platform for Websites and APIs.<\/figcaption><\/figure>\n\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p><em>Written by&nbsp;<a href=\"https:\/\/coursinator.com\/instructor\/bogdan-vazzolla\" target=\"_blank\" rel=\"noreferrer noopener\" class=\"broken_link\">Bogdan&nbsp;Vazzolla<\/a>.<\/em><\/p>\n\n\n\n<p><em><a href=\"https:\/\/loadfocus.com\/\">LoadFocus<\/a>&nbsp;is a cloud testing platform,&nbsp;a&nbsp;<a href=\"https:\/\/loadfocus.com\/load-testing\" target=\"_blank\" rel=\"noreferrer noopener\">load and stress testing tool<\/a>&nbsp;which provides the infrastructure to run tests with thousands of concurrent users, from&nbsp;<a href=\"https:\/\/loadfocus.com\/locations\">multiple cloud locations<\/a>, in less than a few minutes, keep history of the results, compare different runs to inspect performance improvements or performance degradation.<\/em>&nbsp;<em>It also supports running&nbsp;<a href=\"https:\/\/loadfocus.com\/jmeter-load-testing\" target=\"_blank\" rel=\"noreferrer noopener\">JMeter load tests from the cloud<\/a><\/em>&nbsp;and&nbsp;<a href=\"https:\/\/loadfocus.com\/page-speed-monitoring\">monitoring and audit web and mobile performance<\/a>.<\/p>\n<!-- pn-faq --><h2>Frequently Asked Questions<\/h2><h3>What does CPU utilisation tell me?<\/h3><p>Whether the server is working or waiting. A busy CPU and a mostly idle one point at completely different causes for the same slow response.<\/p><h3>What does high CPU with low throughput mean?<\/h3><p>Usually inefficient code rather than insufficient hardware. Adding capacity to that makes the same work more expensive without making it faster.<\/p><h3>Should I watch it on the load generator?<\/h3><p>Yes. A saturated generator caps the traffic you produce, and the target then looks healthier than it is because it never received the load you intended.<\/p><!-- \/pn-faq --><!-- pn-related-reading --><h2>Related reading<\/h2><ul><li><a href=\"https:\/\/loadfocus.com\/blog\/2022\/03\/actively-measure-the-right-key-metrics-during-performance-testing\">Measure the Right Key Metrics in Performance Testing<\/a><\/li><li><a href=\"https:\/\/loadfocus.com\/blog\/2021\/04\/what-is-hits-per-second-in-performance-testing\">What is Hits per Second in Performance Testing?<\/a><\/li><li><a href=\"https:\/\/loadfocus.com\/blog\/2025\/05\/unit-testing-vs-functional-testing\">Unit Testing vs Functional Testing Explained<\/a><\/li><\/ul>","protected":false},"excerpt":{"rendered":"<p><span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\"><\/span> <span class=\"rt-time\"> 2<\/span> <span class=\"rt-label rt-postfix\">minutes read<\/span><\/span>Key takeaways CPU utilisation shows whether the server is working or waiting, which changes the diagnosis. High CPU with low throughput usually means inefficient code, not insufficient hardware. Watch it on the load generator too, since a saturated generator caps the test. CPU or Central Processing Unit is the brain of any computer and its&#8230;  <a href=\"https:\/\/loadfocus.com\/blog\/2022\/04\/what-is-cpu-utilization-in-performance-testing\" class=\"more-link\" title=\"Read What is CPU Utilization in Performance Testing?\">Read more &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":2435,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[48],"tags":[389,390],"class_list":["post-2433","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-test-automation","tag-cpu-usage","tag-processor-usage"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/posts\/2433","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/comments?post=2433"}],"version-history":[{"count":1,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/posts\/2433\/revisions"}],"predecessor-version":[{"id":2764,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/posts\/2433\/revisions\/2764"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/media\/2435"}],"wp:attachment":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/media?parent=2433"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/categories?post=2433"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/tags?post=2433"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}