I have now figured out the problem: when testing with a whole partition "/dev/sdb1" and specifying an offset you have also to specify a size via "--size". I thought that if I am using an offset with a partition Fio would carry out the test starting at the offset until the end of the partition. But this is not the case, you have to explicitly give the rest of partition's size starting from the offset. This was my fault, Fio is doing everything correctly. -Georg ----- Ursprüngliche Mail ----- Von: "Georg Schönberger" <gschoenberger@xxxxxxxxxxxxxxxx> An: fio@xxxxxxxxxxxxxxx Gesendet: Mittwoch, 18. Juli 2012 19:56:52 Betreff: Problem using --offset: fix call to fadvise64 Hello everybody, I don't know if it is a bug but my usage of the offset parameter seems not to work correctly. In detail the offset call works, but at a certain size the call to "fadvise64" is no longer correct: Here is the working offset: # strace -o fio.out.working -f fio --rw=read --name=usb-stick --bs=1024k --direct=1 --filename=/dev/sdb1 --runtime=10 --time_based --offset=1024 usb-stick: (g=0): rw=read, bs=1M-1M/1M-1M, ioengine=sync, iodepth=1 fio-2.0.8-2-gd3987 Starting 1 process Jobs: 1 (f=1): [R] [100.0% done] [19320K/0K /s] [18 /0 iops] [eta 00m:00s] usb-stick: (groupid=0, jobs=1): err= 0: pid=20570 read : io=195584KB, bw=19492KB/s, iops=19 , runt= 10034msec [...] # grep fadvise fio.out.working 20570 fadvise64(3, 1024, 20970496, POSIX_FADV_SEQUENTIAL) = 0 With an offset more than half of the device, the overall device size is no longer correct (should be 20970496 again): # strace -o fio.out -f fio --rw=read --name=usb-stick --bs=1024k --direct=1 --filename=/dev/sdb1 --runtime=10 --time_based --offset=10485760 usb-stick: (g=0): rw=read, bs=1M-1M/1M-1M, ioengine=sync, iodepth=1 fio-2.0.8-2-gd3987 Starting 1 process Run status group 0 (all jobs): Disk stats (read/write): sdb: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00% # grep fadvise fio.out 20848 fadvise64(3, 10485760, 10485760, POSIX_FADV_SEQUENTIAL) = 0 As the call to fadvise64 is not correct (instead of 10485760 as the 3rd parameter there should be 20970496) the job does not start. I am using the latest fio version: # fio --version fio-2.0.8-9-gfb9f0 -Georg -- 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 -- 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
