> Is there anything like that to contorl/limit user's resource usage on shared hosting server?
Most shared hosting environments (including Plesk, cPanel, Ensim and even your typical home-grown hosting environment) run all domains and code as a single user, mainly the 'apache' or 'nobody' user. So using ulimit or pam_limits will not work to limit a particular user or domains resource usage.
If you run the command 'top' you can reveal what process is taking up the largest amounts of the cpu -- but it will take deeper inspection to find out which domain or user is actually using those resources.
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