I'm trying to benchmark the thundering herds probem with flock(),
but either flock() is broken or I made a stupid mistake.
I use
- kernel 2.2.7, kernel 2.2.3 (compiled by RH)
- ext2 filesystem
- egcs (sorry, I don't have gcc 2.7.2)
- glibc-2.1.1-6 (RH 6.0)
Could someone compile the attached program, and
send me the results?
The attached program creates a small shm segment,
a lock file & uses flock() to synchronize the access to
the memory segment.
The probem is that the synchronization fails:
on UP: "./a.out 1000 10" fails after 5-10 second
on SMP (2*PII): "./a.out 1000 2" fails nearly immediately.
Please Cc, I'm not on the mailing list.
I've checked, sys_flock() is called, it creates a write lock.
Thanks,
Manfred
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