The syscall overhead isn&#x27;t the problem, that&#x27;s dirt cheap as you say. The problem is the context-switch overhead. Calling into the OS flushes a lot of data and instructions from the cache, and that lost performance after returning can easily add up to around 30µs.[1]<p>[1] <a href="http:&#x2F;&#x2F;blog.tsunanet.net&#x2F;2010&#x2F;11&#x2F;how-long-does-it-take-to-make-context.html" rel="nofollow">http:&#x2F;&#x2F;blog.tsunanet.net&#x2F;2010&#x2F;11&#x2F;how-long-does-it-take-to-ma...</a>