Hi Rob, Since pr_size and pr_rssize are size_t's, I'm guessing that they're zero since the number is too big to represent in 32 bits, so the field is being made 0 instead. If you compile your C program for 64-bit (-m64 for GCC, I believe), does the output change?
- Cody On Mon, Apr 10, 2017 at 5:08 PM, Robert Fisher <[email protected]> wrote: > I've been writing some software which parses `/proc` to get process info. > The original is in Python, but I got some unexpected results and, as I'm > not the best with Python, assumed it was my bad coding. So, I wrote a bit > of C to cross-reference, and I get the same results. I just can't > understand why. > > ----- > #include <stdio.h> > #include <unistd.h> > #include <procfs.h> > #include <fcntl.h> > > static void print_info(psinfo_t *buf); > > void main(int argc, char **argv) { > psinfo_t buf; > int fd; > char file [1024]; > snprintf(file, 1024, "/proc/%s/psinfo", argv[1]); > fd = open(file, O_RDONLY); > read(fd, &buf, sizeof(psinfo_t)); > close(fd); > print_info(&buf); > } > > static void print_info(psinfo_t *buf) { > printf(" PID: %ld\n", buf->pr_pid); > printf(" cmd: %s\n", buf->pr_psargs); > printf("size: %ld\n", buf->pr_size); > printf(" RSS: %ld\n", buf->pr_rssize); > } > > ----- > > Obviously, this code parses a process's psinfo struct, and prints the > memory usage. On some processes it works just fine: > > $ ./psinfo 27481 > PID: 27481 > cmd: /usr/sbin/cron > size: 2132 > RSS: 720 > > $ ./psinfo 8715 > PID: 8715 > cmd: /usr/bin/java -Djava.library.path=/usr/local/graylog/bin/../lib/sigar > -Xms256m > size: 519536 > RSS: 412148 > > But on others, it always shows zero for memory usage. Every other field > seems to be correct. > > $ ./psinfo 28352 > PID: 28352 > cmd: java -Xmx500m -Xms300m -server -verbosegc -XX:-UseParallelOldGC > -XX:OnOutOfMemo > size: 0 > RSS: 0 > > $ ./psinfo 27627 > PID: 27627 > cmd: /ops/local/mysql/bin/mysqld --defaults-file=/opt/local/ > etc/mysql/my.cnf > size: 0 > RSS: 0 > > Examining that last process with prstat: > > $ prstat -cp 27627 1 1 > Please wait... > PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP > > 27627 mysql 619M 379M sleep 28 0 0:01:28 0.0% mysqld/23 > Total: 1 processes, 23 lwps, load averages: 0.12, 0.15, 0.21 > > DTracing that command, I can see prstat only looks at /proc/{pid}/psinfo, > just like my C example. (At first I suspected it was doing something with > LWP info.) Looking at the source suggests my code and prstat are doing the > same thing, but one works and one doesn't. > > The "zero memory" processes are always the same ones. Some programs always > report it, and the others never do. It seems particularly odd to me that > some JVMs "work" and some don't, and it's always the same ones. I get > identical results on a Solaris box, right down to the same Java programs > working or not working. > > What's going on here? What am I missing? > > TIA, > > > Rob > *smartos-discuss* | Archives > <https://www.listbox.com/member/archive/184463/=now> > <https://www.listbox.com/member/archive/rss/184463/27398174-11508a73> | > Modify > <https://www.listbox.com/member/?&;> > Your Subscription <http://www.listbox.com> > ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
