Hello, I'm currently looking at one NVRAM device, and during fio tests noticed that each fio thread consumes 30% of user space CPU. I'm using ioengine=libaio, buffered=0, sync=0 and direct=1, so user space CPU consumption should be virtually zero. That 30% user CPU consumption makes me suspect that this is overhead for internal fio housekeeping, i.e., scientifically speaking, fio instrumental measurement mistake (I hope, I'm using correct English terms). Can anybody comment it and suggest how to decrease this user space CPU consumption? Here is my full fio job: [global] ioengine=libaio buffered=0 sync=0 direct=1 randrepeat=1 softrandommap=1 rw=randread bs=4k filename=./nvram (it's a link to a block device) exitall=1 thread=1 disable_lat=1 disable_slat=1 disable_clat=1 loops=10 iodepth=16 [file1] [file2] I'm working on million+ IOPS range. Thanks, Vlad -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
