2.6.20: stripe_cache_size goes boom with 32mb

[Justin Piszcz]

Each of these are averaged over three runs with 6 SATA disks in a SW RAID 
5 configuration:

(dd if=/dev/zero of=file_1 bs=1M count=2000)

128k_stripe: 69.2MB/s
256k_stripe: 105.3MB/s
512k_stripe: 142.0MB/s
1024k_stripe: 144.6MB/s
2048k_stripe: 208.3MB/s
4096k_stripe: 223.6MB/s
8192k_stripe: 226.0MB/s
16384k_stripe: 215.0MB/s

When I tried a 32768k stripe, this happened:
p34:~# echo 32768 > /sys/block/md4/md/stripe_cache_size
Connection to p34 closed

I was able to Alt-SysRQ+b but I could not access the console/X/etc, it 
appeared to be frozen.

FYI.

Justin.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/