Re: Sockets and Sleep Question
On Thu, Oct 03, 2002 at 05:12:38PM -0700, Jessee Parker wrote:
I will definitely take a look at this. How do you determine what your
current nice status is?
nice, with no arguments, will give you your current nice level. ps and top
will diplay the nice level (or sometimes priority) of processes. Also,
BSD::Resource, found on CPAN, has a method for retrieving a process's
priority. I'm fairly certain there are more ways of getting the information.
How did you verify the condition was never reached? If you determined it
independently of the program printing to its log file then I'd have to see
the code to be able to tell you what's going on.
What I did was had top running and watched the load average.
Ok, the test was seperate. Have you tried running strace on the program to
see where it's sleeping? Are you certain it's sleeping, or is it possible
it's blocking on a read or write?
The code I am using to check the load average is this:
$highload = .8;
while (($currload = Load) $highload)
{
print LOG Sleeping\n;
sleep 5;
}
sub Load {
# Test system load and wait if it's too high
@uptime = split(/,/, `uptime`);
$fraction = $uptime[3];
$load = (split /:/, $fraction)[1];
return $load;
}
This code doesn't work for me, though it may be because of a difference in
uptime output. Have you verified Load() returns the value you expect?
Also, Load has slightly different meaning from Load(), due to the . It
doesn't look like it will effect you here, but you should check perldoc
perlsub for the difference between them.
Michael
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Re: Sockets and Sleep Question
On Thu, Oct 03, 2002 at 10:10:34AM -0700, Jessee Parker wrote: At the top of the loop, I check the system uptime to get the load average so I can have the program sleep for 5 seconds to let things stabilize a bit. I suspect an easier way of doing this would be to nice yourself down really low; see man nice. There may be a Perl module available on CPAN for doing this, as well. When this happens, the message Sleeping is printed out to a log file. However, I noticed that the program ended up sleeping without printing the message. It sounds to me like you might be having a buffering issue; while the process did print before going to sleep, the output was never flushed to the file. See http://perl.plover.com/FAQs/Buffering.html. The condition I set for load average was never reached so there was no reason for it to sleep. I ran a netstat -an and there were alot of tcp connections to port 25 in the TIME_WAIT mode. How did you verify the condition was never reached? If you determined it independently of the program printing to its log file then I'd have to see the code to be able to tell you what's going on. What I'm trying to figure out is if the OS or Perl itself puts a limit on processes when it has a large number of connections in that mode forcing it to sleep. I am running this on Redhat Linux version 7.3. Unix operating systems do have methods of limiting the number of open file descriptors for a given process, as well as system-wide. However, the typical response when you reach this limit is to kill the offending process, not to put it to sleep. This is how Linux process limits operate. Perl doesn't impose limits on resource usage. Michael -- Administrator www.shoebox.net Programmer, System Administrator www.gallanttech.com -- -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Sockets and Sleep Question
On Thu, Oct 03, 2002 at 10:10:34AM -0700, Jessee Parker wrote:
At the top of the loop, I check the system uptime to get the load
average
so I can have the program sleep for 5 seconds to let things stabilize a
bit.
I suspect an easier way of doing this would be to nice yourself down
really
low; see man nice. There may be a Perl module available on CPAN for doing
this, as well.
I will definitely take a look at this. How do you determine what your
current nice status is?
When this happens, the message Sleeping is printed out to a log file.
However, I noticed that the program ended up sleeping without printing
the
message.
It sounds to me like you might be having a buffering issue; while the
process did print before going to sleep, the output was never flushed to
the
file. See http://perl.plover.com/FAQs/Buffering.html.
The condition I set for load average was never reached so there was no
reason for it to sleep. I ran a netstat -an and there were alot of tcp
connections to port 25 in the TIME_WAIT mode.
How did you verify the condition was never reached? If you determined it
independently of the program printing to its log file then I'd have to see
the code to be able to tell you what's going on.
What I did was had top running and watched the load average. The code I am
using to check the load average is this:
$highload = .8;
while (($currload = Load) $highload)
{
print LOG Sleeping\n;
sleep 5;
}
sub Load {
# Test system load and wait if it's too high
@uptime = split(/,/, `uptime`);
$fraction = $uptime[3];
$load = (split /:/, $fraction)[1];
return $load;
}
The buffering information is great, but I will have to wait until the
next run to see if that is indeed why Sleeping isn't being printed out.
When I do local tests, I can print Sleeping to the screen with no problem.
Even when I take out the LOG in the above, Sleeping does not get printed
out with an actual run of data (an actual run being subscriber e-mail
addresses versus e-mail accounts I have set up on various sites for
testing).
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sleep question
Greetings, I have a script that forks 5 children. I print to screen when each child gets forked. Under certain conditions in the script a child should sleep. This conditions occurs at different times for each child. I think I am noticing that when the sleep is called in a child, every child and the parent sleep as well. Am I correct in this assumption? The OS that the script is running on is Solaris. Thanks, CHad -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: sleep question
-Original Message- From: Chad Kellerman [mailto:[EMAIL PROTECTED]] Sent: Thursday, September 12, 2002 12:37 PM To: [EMAIL PROTECTED] Subject: sleep question Greetings, I have a script that forks 5 children. I print to screen when each child gets forked. Under certain conditions in the script a child should sleep. This conditions occurs at different times for each child. I think I am noticing that when the sleep is called in a child, every child and the parent sleep as well. Am I correct in this assumption? No. After the fork, parent and child lead separate lives. Something else is going on. The OS that the script is running on is Solaris. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
