Security in versions of OS X has been updated with the no-root theme with System Integrity Protection. Unfortunately that also includes dtrace and commands like iotop that rely on it. One can reboot a Mac into recovery mode and fix it however…
Enter Terminal in Recovery mode and type this command:
csrutil disable
Better not to keep it turned off: Disable it only for dtrace… (2 dashes before ‘without’)
csrutil enable ––without dtrace
It will complain about being an unsupported configuration, ignore it. Proceed anyway.
Then reboot.
If you wish to return it to the default, enter the Recovery Mode Terminal again and enter the opposite command:
csrutil enable
Then reboot and all is reset to the way it was before you made any changes.
IT Director/Senior Software Engineer, Photographer I test and create new CSS web page formatting hacks for BrowserHacks.com for the purpose of repairing web sites. PS-- CSS hacks are fun, but please attempt good CSS first unless in a bind. See Test Pages: https://browserstrangeness.bitbucket.io and https://browserstrangeness.github.io
Jeff Clayton IT Director / Senior Software Engineer / Film & Photography 
Apparently it’s “double dash without”. It renders as a single dash in my browser.
Thanks for the info!
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you are right, 2 dashes – i added a few extra html tags around the dashes to force it — thanks for the note!
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Esto es una Experiensia Muy buena
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