> did you benchmark with anything other than dbench ?
No, and I really don't want to hear how dbench is a terrible benchmark.
I didn't craft the patch around dbench and I think, here at least,
dbench is an OK benchmark. I ran it numerous times over multiple client
loads.
I think its clear there won't be a negative impact, because:
- acquiring the inode semaphore isn't any heavier (in the acquire
case) than the BKL
- the lock contention on each inode semaphore is relatively
zero
- besides just scaling badly with the using a global lock against
all inodes, we use the BKL which in such workloads is already
highly contested.
That said, I did do some lock profiling and latency tests. Contention
was near-zero, but I only did 2-way testing. Under the preemptible
kernel, while running dbench, scheduling latency improved 8.9%.
Robert Love
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/