[lug] Web crawler advice
nate at natetech.com
Mon May 5 12:22:56 MDT 2008
George Sexton wrote:
> OTOH, threading in Java is dead easy, and this kind of app would benefit
> from multi-threading.
Dead-easy until it blows up. :-)
Threading is starting to get as bad a rap as "goto" got in the 70s.
The author specifically talks about how subtle problems will crop up on
multi-core machines, especially.
Had something similar lately. The symptom was that Perl wouldn't start
on a 4-processor Sun box.
Perl (for some UNHOLY reason) uses floating-point math to compare the
main perl version number with the version numbers in any modules it
loads at run-time.
What had happened was that the FPU in CPU #3 on the box was flaky.
Since it was running very little else that required floating-point
calculations, the only "symptom" was, "Perl won't run consistently, or
dies halfway through scripts!" (The scripts that were dying were
loading more modules.
Frackin' ugly troubleshooting session that was... until we "caught" the
FPU doing naughty things with Sun's hardware test tools.
I shudder to think how long that would have taken on PeeCee hardware
where such test tools simply don't (really) exist on most hardware/OS
More information about the LUG