Messages in this thread |  | | Date | Mon, 09 Oct 2000 19:36:59 +1000 | From | Robert Cohen <> | Subject | [Bench] Slow tiotest read in Kernel 2.2.16+ |
| |
Ive been seeing poor read results from tiotest in recent 2.2 kernels since 2.2.16. The performance is fine with 1 thread but slows right down with 8. I include the tiotest results here but I see similar results with iozone -t.
Kernel 2.2.15
[robert@testmac25 robert]$ tiotest -f 30 -t 8 -r 0 Tiotest results for 8 concurrent io threads:
,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 240 MBs | 20.8 s | 11.533 MB/s | 0.3 % | 14.0 % | | Read 240 MBs | 19.2 s | 12.531 MB/s | 0.3 % | 8.9 % | `----------------------------------------------------------------------'
Kernel 2.2.16
[robert@testmac25 robert]$ tiotest -f 30 -t 8 -r 0 Tiotest results for 8 concurrent io threads:
,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 240 MBs | 23.9 s | 10.058 MB/s | 0.0 % | 12.8 % | | Read 240 MBs | 105.4 s | 2.276 MB/s | 0.1 % | 2.5 % | `----------------------------------------------------------------------'
Kernel 2.2.18pre15
[robert@testmac25 robert]$ tiotest -f 30 -t 8 -r 0 Tiotest results for 8 concurrent io threads:
,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 240 MBs | 22.5 s | 10.688 MB/s | 0.3 % | 12.5 % | | Read 240 MBs | 98.0 s | 2.450 MB/s | 0.1 % | 2.7 % | `----------------------------------------------------------------------'
Robert Cohen TLTSU Unix Support Australian National University - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
|  |