Hi Andy, I'm looking at TCMU's performance. Just played with tcmu-runner/file_example ... root@target:~# cat /proc/partitions major minor #blocks name 259 0 937692504 nvme0n1 259 1 1048576 nvme0n1p1 8 32 1048576 sdc 8 48 1048576 sdd Frontend for both sdc and sdd is loopback Backend for sdc is iblock Backend for sdd is tcmu The underlying device is /dev/nvme0n1p1 /dev/nvme0n1p1: Jobs: 4 (f=4): [rrrr] [100.0% done] [967.2MB/0KB/0KB /s] [248K/0/0 iops] [eta 00m:00s] /dev/sdc(iblock loopback): Jobs: 4 (f=4): [rrrr] [100.0% done] [965.6MB/0KB/0KB /s] [247K/0/0 iops] [eta 00m:00s] /dev/sdd(tcmu loopback): 1) First test: drop cache, throughput only about 66M echo 3 > /proc/sys/vm/drop_caches Jobs: 4 (f=4): [rrrr] [100.0% done] [66592KB/0KB/0KB /s] [16.7K/0/0 iops] [eta 00m:00s] 2) Second test，the data is already in page cache, so super fast Jobs: 4 (f=4): [rrrr] [100.0% done] [1360MB/0KB/0KB /s] [348K/0/0 iops] [eta 00m:00s] I guess the poor performance comes from tcmu-runner/file_example.c. I'll try to modify file_example.c to use AIO+DIO. My goal is to verify whether tcmu's file handler can get similar performance as iblock. What do you think? Thanks, Ming -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
