* cronfy <cro...@gmail.com> [100124 15:59] wrote: > Hello. > > Sorry for the crosspost, I intended to post this to freebsd-hackers@, but > sent first copy to freebsd-questions@ by mistake. > > > I am trying to create an accounting daemon that would be more precise > than usual BSD system accounting. It should read the whole process > tree from time to time (say, every 10 seconds) and log changes in > usage of CPU, I/O operations and memory per process. After daemon > notices process exit, it should read /var/account/acct to get a last > portion of accounting data and make a last entry for the process. Also > daemon should read /var/account/acct to find information about > processes that had been running between taking process tree snapshots. > > There is a problem: it is not always possible to link a process in a > process tree against matching process in an accounting file. Only > command name, user/group id and start time will match, but: > > * start time may change (i. e. after ntpdate); > * command name saved in /var/account/acct is 15 characters max > (AC_COMM_LEN in sys/sys/acct.h), while command name in the process > tree is 19 characters max (MAXCOMLEN in sys/sys/param.h). > > To ensure that process in the process tree and process in the > accounting file are the same, I want to add unique process identifier > (uint64_t) to 'proc' struct in sys/sys/proc.h and increment it for > every process fork. I see it is possible to do this just before > sx_sunlock() in fork1() in sys/kern/kern_fork.c. I'll have to add > saving of this identifier in kern_acct.c, of course. > > This way I will be extremely easy to remember a process in the process > tree and find a matching one in the accounting file after it finishes. > > Am I looking in a right direction or should I try some other way? > Thanks in advance.
I've thought of this a few times, specifically how to ensure not sending a signal to a process by accident, specifically adding a version of kill(2) that took process start time. It's interesting that you bring up that start time can change, I did not know this. Now that I know this, I would suggest simply recording the start time as the serial number, then using pid+recorded_start_time as your serial number. Just an idea. -- - Alfred Perlstein .- AMA, VMOA #5191, 03 vmax, 92 gs500, 85 ch250 .- FreeBSD committer _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
