NCQ disabled, 32 disks, 32 threads

heavy# zpool iostat 1
               capacity     operations    bandwidth
pool         used  avail   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
...
test        40.0G  14.5T     37      0  3.66M      0
test        40.0G  14.5T      0      0      0      0
test        40.0G  14.5T    668      0  81.7M      0
test        40.0G  14.5T  2.21K      0   283M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.22K      0   284M      0
test        40.0G  14.5T  2.31K      0   296M      0
test        40.0G  14.5T  2.33K      0   298M      0
test        40.0G  14.5T  2.36K      0   302M      0
test        40.0G  14.5T  2.26K      0   289M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.26K      0   289M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.28K      0   291M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.33K      0   298M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.27K      0   290M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.26K      0   290M      0
test        40.0G  14.5T  2.33K      0   298M      0
test        40.0G  14.5T  2.29K      0   293M      0
test        40.0G  14.5T  2.21K      0   283M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.28K      0   292M      0
test        40.0G  14.5T  2.28K      0   292M      0
test        40.0G  14.5T  2.24K      0   286M      0
test        40.0G  14.5T  2.32K      0   297M      0
test        40.0G  14.5T  2.19K      0   280M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.21K      0   283M      0
test        40.0G  14.5T  2.34K      0   300M      0
test        40.0G  14.5T  2.21K      0   283M      0
test        40.0G  14.5T  2.30K      0   295M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.25K      0   289M      0
test        40.0G  14.5T  2.23K      0   286M      0
test        40.0G  14.5T  2.28K      0   291M      0
test        40.0G  14.5T  2.27K      0   290M      0
test        40.0G  14.5T  2.29K      0   293M      0
test        40.0G  14.5T  2.23K      0   285M      0
test        40.0G  14.5T  2.28K      0   292M      0
test        40.0G  14.5T  2.27K      0   290M      0
test        40.0G  14.5T  2.24K      0   286M      0
test        40.0G  14.5T  2.23K      0   286M      0
test        40.0G  14.5T  2.30K      0   295M      0
test        40.0G  14.5T  2.29K      0   293M      0
test        40.0G  14.5T  2.19K      0   281M      0
test        40.0G  14.5T  2.32K      0   296M      0
test        40.0G  14.5T  2.30K      0   294M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.26K      0   290M      0
test        40.0G  14.5T  2.26K      0   290M      0
test        40.0G  14.5T  2.28K      0   291M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.23K      0   285M      0
test        40.0G  14.5T  2.23K      0   286M      0
test        40.0G  14.5T  2.23K      0   286M      0
test        40.0G  14.5T  2.23K      0   285M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.26K      0   289M      0
test        40.0G  14.5T  2.29K      0   293M      0
test        40.0G  14.5T  2.31K      0   295M      0
test        40.0G  14.5T  2.22K      0   284M      0
test        40.0G  14.5T  2.26K      0   289M      0
test        40.0G  14.5T  2.28K      0   292M      0
test        40.0G  14.5T  2.21K      0   282M      0
test        40.0G  14.5T  2.28K      0   292M      0
test        40.0G  14.5T  2.20K      0   281M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.28K      0   292M      0
test        40.0G  14.5T  2.27K      0   290M      0
test        40.0G  14.5T  2.20K      0   281M      0
test        40.0G  14.5T  2.26K      0   289M      0
test        40.0G  14.5T  2.29K      0   293M      0
test        40.0G  14.5T  2.22K      0   284M      0
test        40.0G  14.5T  2.22K      0   284M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.19K      0   281M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.29K      0   293M      0
test        40.0G  14.5T  2.19K      0   280M      0
test        40.0G  14.5T  2.29K      0   294M      0
test        40.0G  14.5T  2.23K      0   285M      0
test        40.0G  14.5T  2.23K      0   285M      0
test        40.0G  14.5T  2.22K      0   284M      0
test        40.0G  14.5T  2.20K      0   281M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.20K      0   281M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.24K      0   287M      0
test        40.0G  14.5T  2.22K      0   285M      0
test        40.0G  14.5T  2.26K      0   289M      0
test        40.0G  14.5T  2.22K      0   284M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.23K      0   285M      0
test        40.0G  14.5T  2.22K      0   285M      0
test        40.0G  14.5T  2.28K      0   292M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.29K      0   293M      0
test        40.0G  14.5T  2.24K      0   286M      0
test        40.0G  14.5T  2.36K      0   302M      0
test        40.0G  14.5T  2.18K      0   279M      0
test        40.0G  14.5T  2.23K      0   286M      0
test        40.0G  14.5T  2.25K      0   289M      0
test        40.0G  14.5T  2.21K      0   283M      0
test        40.0G  14.5T  2.24K      0   286M      0
test        40.0G  14.5T  2.25K      0   289M      0
test        40.0G  14.5T  2.22K      0   284M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.23K      0   286M      0
test        40.0G  14.5T  2.26K      0   290M      0
test        40.0G  14.5T  2.22K      0   285M      0
test        40.0G  14.5T  2.25K      0   288M      0
test        40.0G  14.5T  2.28K      0   291M      0
test        40.0G  14.5T  2.27K      0   291M      0
test        40.0G  14.5T  2.18K      0   279M      0
test        40.0G  14.5T    701      0  87.6M      0