On Thu, Jan 10 2008, Pei Yan wrote: > Hi, > > 8,16 0 8 0.000594537 3420 Q R 1318936 + 8 [fio] > 8,16 0 9 0.000596873 3420 G R 1318936 + 8 [fio] > 8,16 0 10 0.000597670 3420 P N [fio] > 8,16 0 11 0.000598051 3420 I R 1318936 + 8 [fio] > 8,16 0 12 0.000600492 3420 D R 1318936 + 8 [fio] > 8,16 0 13 0.000669173 3420 U N [fio] 1 > > 8,16 0 14 0.015246002 3380 C R 1318936 + 8 [0] > 8,16 0 15 0.121368302 3421 Q R 12328 + 8 [fio] > 8,16 0 16 0.121376327 3421 G R 12328 + 8 [fio] > 8,16 0 17 0.121378041 3421 P N [fio] > 8,16 0 18 0.121378833 3421 I R 12328 + 8 [fio] > 8,16 0 19 0.121381194 3421 U N [fio] 1 > 8,16 0 20 0.121732327 3422 Q R 1576976 + 8 [fio] > 8,16 0 21 0.121735570 3422 G R 1576976 + 8 [fio] > 8,16 0 22 0.121736232 3422 I R 1576976 + 8 [fio] > 8,16 0 23 0.121737335 3422 U N [fio] 2 > > 8,16 0 24 0.128906924 17 D R 12328 + 8 [kblockd/0] > > 8,16 0 25 0.129079556 0 C R 12328 + 8 [0] > 8,16 0 26 0.129139932 3421 Q R 12336 + 8 [fio] > 8,16 0 27 0.129142609 3421 G R 12336 + 8 [fio] > 8,16 0 28 0.129143370 3421 I R 12336 + 8 [fio] > 8,16 0 29 0.129145791 3421 D R 12336 + 8 [fio] > 8,16 0 30 0.129213867 3421 U N [fio] 2 > > 8,16 0 31 0.129276092 0 C R 12336 + 8 [0] > > > Q: why are the pids in four tagged lines above changed? For example, in the > first tagged line, the pid related to the same request(1318936 + 8) changes > to 3380 from 3420. Why? The pid denotes who did the action listed. So for eg completions, they typically happen from irq context and thus aren't specific to a process. > Are there any methods to ensure that all activities initiated by a process > be all tagged with the pid of that initiating process? No, you should track by location like blkparse does. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-btrace" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
