There are two issues here: an OS one, and a perl one. First, why the OS won't allow the fork. Linux usually allows a certain amount of overcommitting of swap, which would normally safely allow the fork followed by exec to run the date command. My back-of-the envelope calculations on the size of the perl process seems to have been low - from your numbers, it looks like the 32-bit perl is 2482Mb, while the 64-bit one is 3165Mb. This means the 64-bit one can't fork without overcommitting. Perhaps you've disabled overcommitting on your systems? Mine show the following, which are the defaults: 
# cat /proc/sys/vm/overcommit_memory 
0
# cat /proc/sys/vm/overcommit_ratio 
50

[download]

The perl issue is why the ENOMEM from the clone sys call isn't getting reported by the perl fork function. This smells like a bug.

Dave.

In reply to Re^6: system command - OK on 32 bit, fails on 64 bit Linux - why? by dave_the_m
in thread system command - OK on 32 bit, fails on 64 bit Linux - why? by geep999

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