The sysctl option “kernel.core_uses_pid” comes into play when a vmcore file is being dumped.  It can be set in one of two ways;

kernel.core_uses_pid = 0

or

kernel.core_uses_pid = 1

As you can probably tell this is a binary settings.  It’s either enabled (1) or it’s not (0).

The exact text from the sysctl.txt file is;

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core_uses_pid:

The default coredump filename is "core".  By setting
core_uses_pid to 1, the coredump filename becomes core.PID.
If core_pattern does not include "%p" (default does not)
and core_uses_pid is set, then .PID will be appended to
the filename.

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For Fedora 22 this parameter is set to “1” by default.