title: R - mclapply takes more processors than it should and is slower
body: <p>I am trying to fix an issue that I came across in one of my lab servers.
  When I use mclapply on server A using 30 processors it behaves as expected:
  <a href="https://user-images.githubusercontent.com/26927889/167973438-55f5c60c-b8ba-45b9-a31f-b17004a79e45.png" rel="nofollow noreferrer">https://user-images.githubusercontent.com/26927889/167973438-55f5c60c-b8ba-45b9-a31f-b17004a79e45.png</a></p>
  <p>Then when switching to server B using just 5 processors:
  <a href="https://user-images.githubusercontent.com/26927889/167973523-d705d66f-4721-4436-a0bf-54a2ee466bcc.png" rel="nofollow noreferrer">https://user-images.githubusercontent.com/26927889/167973523-d705d66f-4721-4436-a0bf-54a2ee466bcc.png</a></p>
  <p>The code I am using is kinda long, but I launch mclapply in this way:</p>
  <pre><code>mclapply(1:length(peak.list), function(x) GLM(gene,x), mc.cores = 5)
  </code></pre>
  <p>I have no idea why server B behaves like that, it is using more processors than I ask and going way slower.</p>
  <p>I tried to <code>detectCores(logical = FALSE)</code> or <code>detectCores()</code> and the answer is always 80 cores.</p>
  <p>Ideas? What should I check?!</p>