Question

I'm a new user of IOzone, when I run the IOzone with the command: ./iozone -i 0 -i 1 -t 2 -T, it generates the following result(partially):

Command line used: ./iozone -i 0 -i 1 -t 2 -T
Output is in Kbytes/sec
Time Resolution = 0.000001 seconds.
Processor cache size set to 1024 Kbytes.
Processor cache line size set to 32 bytes.
File stride size set to 17 * record size.
Throughput test with 2 threads
Each thread writes a 512 Kbyte file in 4 Kbyte records
Children see throughput for  2 initial writers  =  650943.69 KB/sec
Parent sees throughput for  2 initial writers   =   13090.24 KB/sec
Min throughput per thread           =  275299.72 KB/sec 
Max throughput per thread           =  375643.97 KB/sec
Avg throughput per thread           =  325471.84 KB/sec
Min xfer                    =     356.00 KB

Children see throughput for  2 rewriters    = 1375881.50 KB/sec
Parent sees throughput for  2 rewriters     =   10523.74 KB/sec                                                
Min throughput per thread           = 1375881.50 KB/sec 
Max throughput per thread           = 1375881.50 KB/sec
Avg throughput per thread           =  687940.75 KB/sec
Min xfer                    =     512.00 KB

Children see throughput for  2 readers      = 2169601.25 KB/sec
Parent sees throughput for  2 readers       =   27753.94 KB/sec
Min throughput per thread           = 2169601.25 KB/sec 
Max throughput per thread           = 2169601.25 KB/sec
Avg throughput per thread           = 1084800.62 KB/sec
Min xfer                    =     512.00 KB

Children see throughput for 2 re-readers    = 2572435.25 KB/sec
Parent sees throughput for 2 re-readers     =   26311.78 KB/sec
Min throughput per thread           = 2572435.25 KB/sec 
Max throughput per thread           = 2572435.25 KB/sec
Avg throughput per thread           = 1286217.62 KB/sec
Min xfer                    =     512.00 KB

iozone test complete.

I get confused about meaning of "throughput" and "Min xfer", is there someone can help me? By the way, why the throughput seen from children and parent is different? Thanks!

No correct solution

OTHER TIPS

Min xfer refers to the smallest amount of data written at one time. "Each thread writes a 512 Kbyte file in 4 Kbyte records"

So if the Min xfer was 512.00 KB it wrote the entire actual file to disk at once (grouped all the 4 Kbyte records together).

Children and parent throughput are different due to OS I/O buffering. iozone doesn't force direct (non-buffered) read or writes with the throughput test. What you're really testing is your system's buffer cache + disk cache + disk speed combo.

Licensed under: CC-BY-SA with attribution
Not affiliated with StackOverflow
scroll top