in reply to Re: Why use threads over processes, or why use processes over threads?
in thread Why use threads over processes, or why use processes over threads?

Can you do us a favor, modify your thread program a little bit, and get another set of number (under the same testing environment)?

My suggested modification is to detach threads when they get created, so you explicitly tell Perl that, no join will be done later, and Perl doesn't need waste time/space to keep return structures. (Trust this situation will be changed in future versions.)

threads->create(\&blah)->detach();

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I really appreciate it.

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Re: Why use threads over processes, or why use processes over threads?
by Abigail-II (Bishop) on Nov 11, 2003 at 23:14 UTC
    Well, I gave you the source, so you could have easily done this yourself. Now I had to first compile a threaded Perl (as I'm on a different machine now). Anyway, I modified the program so it does it all four times: fork and wait, fork with SIGCHLD being ignored, joining threads, and detachted threads, with labels Fw, Fi, Tj and Td. Not surprisingly, there's not much difference between Fw and Fi, and between Tj and Td. 
    Empty childs
(Fw)     0: 0.01 user, 0.01 system, 0:00.02 elapsed
(Fi)     0: 0.01 user, 0.00 system, 0:00.01 elapsed
(Tj)     0: 0.05 user, 0.00 system, 0:00.06 elapsed
(Td)     0: 0.05 user, 0.00 system, 0:00.06 elapsed
(Fw)     5: 0.01 user, 0.00 system, 0:00.01 elapsed
(Fi)     5: 0.02 user, 0.00 system, 0:00.02 elapsed
(Tj)     5: 0.11 user, 0.02 system, 0:00.14 elapsed
(Td)     5: 0.12 user, 0.00 system, 0:00.14 elapsed
(Fw)    10: 0.01 user, 0.00 system, 0:00.03 elapsed
(Fi)    10: 0.01 user, 0.00 system, 0:00.03 elapsed
(Tj)    10: 0.20 user, 0.00 system, 0:00.24 elapsed
(Td)    10: 0.21 user, 0.00 system, 0:00.24 elapsed
(Fw)    25: 0.00 user, 0.06 system, 0:00.10 elapsed
(Fi)    25: 0.01 user, 0.01 system, 0:00.09 elapsed
(Tj)    25: 0.45 user, 0.47 system, 0:01.32 elapsed
(Td)    25: 0.42 user, 0.04 system, 0:00.58 elapsed
(Fw)    50: 0.01 user, 0.00 system, 0:00.11 elapsed
(Fi)    50: 0.01 user, 0.00 system, 0:00.16 elapsed
(Tj)    50: 0.86 user, 0.01 system, 0:01.07 elapsed
(Td)    50: 0.79 user, 0.07 system, 0:01.00 elapsed
(Fw)   100: 0.02 user, 0.00 system, 0:00.21 elapsed
(Fi)   100: 0.01 user, 0.00 system, 0:00.35 elapsed
(Tj)   100: 1.60 user, 0.12 system, 0:01.99 elapsed
(Td)   100: 1.62 user, 0.08 system, 0:01.99 elapsed
(Fw)   250: 0.01 user, 0.00 system, 0:00.50 elapsed  
(Fi)   250: 0.02 user, 0.00 system, 0:00.85 elapsed  
(Tj)   250: 4.20 user, 0.23 system, 0:05.18 elapsed
(Td)   250: 4.28 user, 0.20 system, 0:05.22 elapsed
(Fw)   500: 0.02 user, 0.00 system, 0:01.01 elapsed
(Fi)   500: 0.02 user, 0.04 system, 0:01.73 elapsed
(Tj)   500: 9.09 user, 0.56 system, 0:11.28 elapsed
(Td)   500: 9.19 user, 0.46 system, 0:11.25 elapsed  
(Fw)  1000: 0.01 user, 0.01 system, 0:02.02 elapsed  
(Fi)  1000: 0.02 user, 0.12 system, 0:03.47 elapsed
A thread exited while 48 threads were running.
(Tj)  1000: 17.54 user, 14.73 system, 3:07.04 elapsed
(Td)  1000: 22.57 user, 23.33 system, 4:38.73 elapsed

Childs writing
(Fw)     0: 0.03 user, 0.07 system, 0:01.50 elapsed
(Fi)     0: 0.02 user, 0.00 system, 0:00.01 elapsed
(Tj)     0: 0.03 user, 0.04 system, 0:00.83 elapsed
(Td)     0: 0.05 user, 0.00 system, 0:00.06 elapsed
(Fw)     5: 0.02 user, 0.00 system, 0:00.02 elapsed
(Fi)     5: 0.01 user, 0.00 system, 0:00.02 elapsed
(Tj)     5: 0.12 user, 0.02 system, 0:00.17 elapsed
(Td)     5: 0.11 user, 0.02 system, 0:00.14 elapsed
(Fw)    10: 0.01 user, 0.01 system, 0:00.03 elapsed
(Fi)    10: 0.02 user, 0.00 system, 0:00.04 elapsed
(Tj)    10: 0.19 user, 0.01 system, 0:00.23 elapsed
(Td)    10: 0.20 user, 0.01 system, 0:00.26 elapsed
(Fw)    25: 0.02 user, 0.00 system, 0:00.06 elapsed
(Fi)    25: 0.01 user, 0.00 system, 0:00.09 elapsed
(Tj)    25: 0.41 user, 0.04 system, 0:00.53 elapsed
(Td)    25: 0.45 user, 0.01 system, 0:00.53 elapsed
(Fw)    50: 0.01 user, 0.01 system, 0:00.11 elapsed
(Fi)    50: 0.02 user, 0.00 system, 0:00.18 elapsed  
(Tj)    50: 0.81 user, 0.07 system, 0:01.03 elapsed  
(Td)    50: 0.79 user, 0.07 system, 0:01.01 elapsed
(Fw)   100: 0.01 user, 0.00 system, 0:00.21 elapsed
(Fi)   100: 0.02 user, 0.00 system, 0:00.34 elapsed
(Tj)   100: 1.63 user, 0.11 system, 0:02.05 elapsed
(Td)   100: 1.63 user, 0.09 system, 0:01.99 elapsed
(Fw)   250: 0.02 user, 0.01 system, 0:00.52 elapsed  
(Fi)   250: 0.01 user, 0.00 system, 0:00.85 elapsed  
(Tj)   250: 4.22 user, 0.31 system, 0:05.29 elapsed
(Td)   250: 4.28 user, 0.20 system, 0:05.24 elapsed
(Fw)   500: 0.02 user, 0.00 system, 0:01.01 elapsed  
(Fi)   500: 0.01 user, 0.03 system, 0:01.71 elapsed  
(Tj)   500: 9.38 user, 0.51 system, 0:11.50 elapsed
(Td)   500: 9.16 user, 0.54 system, 0:11.28 elapsed
(Fw)  1000: 0.01 user, 0.00 system, 0:02.01 elapsed
(Fi)  1000: 0.02 user, 0.13 system, 0:03.49 elapsed
A thread exited while 51 threads were running.
(Tj)  1000: 17.47 user, 15.01 system, 2:34.14 elapsed
(Td)  1000: 22.57 user, 23.21 system, 5:01.54 elapsed

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    Abigail

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