Is there a clean way to `sudo pkill` processes without including the `sudo` process?

I need to kill some processes that are run as sudo, matching them by full name, and count the number of original command invocations. For each process there are two processes: the command itself, and the sudo one, but I can work this around:

$ sudo -b perf record sleep 100

$ pgrep -fa '/perf record'
2245700 /usr/lib/linux-tools/.../perf record sleep 100

The problem is that when I invoke sudo pkill, it will find, kill and count itself:

$ sudo pkill -ef '/perf record' | wc -l
2

Is there a simple way for pkill not to include itself, in this case? I've tried using pid files, which could be acceptable, but the pgrep/pkill documentation is lacking, and it seems not to work in the basic form:

$ pgrep -f '/perf record' | tee /tmp/pids
$ sudo pkill -F /tmp/pids
 killed (pid 2249211)

as it will kill only the first. The documentation says:

-F, --pidfile file
              Read PID's from file.  This option is perhaps more useful for pkill than pgrep.

but it's ambiguous about the meaning of PID's.