Sergey,
I suspect that what you are seeing has nothing to do with printf buffering. The line is flushed out on \n. What you are seeing is a side effect of monitoring probably lots of threads + aggregation. There is no output until a sampling buffer fills up. With --smpl-entries=1, they fill up quickly but you may have lots of threads. On Thu, Jul 9, 2009 at 11:23 PM, Sergey Blagodurov<blagodu...@gmail.com> wrote: > Hello, > > I was wondering if it's somehow possible to obtain the output from > pfmon unbuffered during sampling. > > What I want to do is to monitor a program's miss rate in real time > with pfmon using the following invocation: > > pfmon --attach-task <pid of the program to monitor> > --smpl-module=compact --smpl-entries=1 --long-smpl-periods=100000000 > --follow-all --aggregate-results -0 -3 > -eUNHALTED_CORE_CYCLES,L2_LINES_IN:SELF > > When I type it in the terminal, all is fine and strings for each > sample show up in real time as soon as they are available. > > Problems start when I try to obtain the same results within c program. > For that I create pipe and then redirect pfmon's stdout into this > pipe. in this case, the results show not in real time, but buffered as > 4k blocks, i.e. only after a block is full, it's being shown on the > other side of the pipe. The same output with delays between the blocks > can be obtained by issuing the following command: > > pfmon --attach-task <pid of the program to monitor> > --smpl-module=compact --smpl-entries=1 --long-smpl-periods=100000000 > --follow-all --aggregate-results -0 -3 > -eUNHALTED_CORE_CYCLES,L2_LINES_IN:SELF | cat > > or by writing into the sample file with --smpl-outfile option: > > pfmon --attach-task <pid of the program to monitor> > --smpl-module=compact --smpl-entries=1 --long-smpl-periods=100000000 > --follow-all --aggregate-results -0 -3 > -eUNHALTED_CORE_CYCLES,L2_LINES_IN:SELF --smpl-outfile=pfmon.log > > At first I thought that the problem is in the pipe itself. However, > the output from some other commands doesn't have this same feature. > For example, the following command brings lines as soon as they appear > without any kind of buffering: > > ping 127.0.0.1 | cat > > Any ideas how I can solve this issue are greatly appreciated. > > Thank you! > > -- > Sincerely, > > Sergey Blagodurov > > ------------------------------------------------------------------------------ > Enter the BlackBerry Developer Challenge > This is your chance to win up to $100,000 in prizes! For a limited time, > vendors submitting new applications to BlackBerry App World(TM) will have > the opportunity to enter the BlackBerry Developer Challenge. See full prize > details at: http://p.sf.net/sfu/Challenge > _______________________________________________ > perfmon2-devel mailing list > perfmon2-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/perfmon2-devel > ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
