Date: Mon, 21 May 2001 14:46:00 +0200 From: Oscar-Ivan Lepe-Aldama <oscar@ac.upc.es> To: questions@freebsd.org Subject: Perfmon device Message-ID: <3B090E07.5201535E@ac.upc.es>
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Hi!
I have noticed that every time the perfmon device is closed it shuts
down the PMECs. While I can see this is appropriate for some
applications, it is not for mine. I'm using the PMECs for measuring the
performance of some in-kernel networking routines. It would be very
useful for me to be able to use the perfmon device for configuring the
PMECs. But as it is distributed this is not possible.
I see two solutions to this. One is to extend the device's
implementation for supporting a "close without stopping" ioctl command.
Because this implies knowing the details of the driver, and because
right now I need a fast solution, I cannot do this.
The other is a brute force (and naive, if you will) solution; that is,
eliminate the code in perfmon_close() that shuts down the PMECs. This
code seams to be at perfmon_fini(), where perfmon_stop() is called and
perfmon_inuse is updated. However, I do not want to do this until I'm
sure such a change is safe. So my question is, can I do such a change an
still get a working device?
Other derived questions. Is there some other way for on-line configuring
the PMECs? Any comment on the proposed extension for the device?
TIA,
--
========================================================================
0 0 0 Oscar-Ivan Lepe-Aldama | UPC-Campus Nord, DAC
0 0 0 e-mail: oscar@ac.upc.es | Modul D6, despatx 116
0 0 0 phone: +34 93 401 7187 | Jordi Girona, 1-3
U P C fax: +34 93 401 7055 | 08034 Barcelona - SPAIN
WWW: http://people.ac.upc.es/homes/oscar/
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