[Perfparse-devel-int] Re: [Perfparse-users] perfparsed & CPU usage

[Tim W. <tim...@gm...>]

Yves,
How much do I get if I told you I've found the solution? 
:)

OK, I admit, it seems odd, but I've encountered this next comment in a
piece of Perl (yes, Perl) code:
# Open the fifo read/write, not just read. This is necessary because
# of the POSIX rules about using select() on named pipes when no writers
# are present. This is a very key step that is hard to find documentation
# about.

(note the last sentence!) 

So I tried exactly that:
change
log_fd[i]->fd = open(filename+1, O_RDONLY);
to
log_fd[i]->fd = open(filename+1, O_RDWR);

and that's it ! Works in 103.2 and 104.1 
(perfparsed 104.1 compiles, but doesn't write anyhting to the db...
:(, but that's another problem I guess. More tomorrow... )

happy coding,
Tim

On Fri, 26 Nov 2004 17:08:42 +0100 (CET), Yves <yme...@pe...> wrote:
> 
> > Yves,
> >
> > Recompiling with the log_source_nonblock(i)  line commented out does
> > not change anything. The CPU still sky-rockets, and the 4 lines still
> > show up (a gazillion times) in strace output.
> 
> So I just suggest that you upgrade to 0.104.1 this week-end, when Ben releases it, and I
> will try to find out why there is always something to read on the pipe for select().
> 
> The only thing I can suggest you now, if you really want a hacked solution, is to put
> this in log_reader() :
> 
> while(10 == (r=read(...))) {
>   ...
> }
> if((r>0) && (r<10)) {
>    ...
> } else if(r == 0) {
>   sleep(1);
> }
> 
> Add the 2 last lines to sleep the program when it reads nothing. The CPU should still
> sky-rocket, but passengers will now have 1 second to get inside the rocket :)
> 
> I will try to find something better for 0.104.2 or 0.105 or course :)
> 
> Yves
> PS. uncomment back log_source_nonblock(i) because it may have side effects.
> 
> --
> 
> 
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> 
>