Thanks Alireza. It was a great help. On Wed, Apr 22, 2015 at 11:57 PM, Alireza Haghdoost <haghdoost@xxxxxxxxx> wrote: > piping blktrace output through blkparse destroys timing accuracy. > Search archive of this mailing list with "Events out of order" keyword > if you what to find out why. However, the short answer is to not use > pipe if the trace timing is important for your. > > On Wed, Apr 22, 2015 at 10:34 PM, Mansour Shafaei Moghaddam > <mansoor.shafaei@xxxxxxxxx> wrote: >> Thanks for your input. So, you mean btt should not be piped with >> blkparse's real time output. right? Because I have run btt offline and >> the only things being piped are blktrace and blkparse which according >> to the manual page of blktrace should not have any problem. >> >> On Wed, Apr 22, 2015 at 11:34 PM, Mansour Shafaei Moghaddam >> <mansoor.shafaei@xxxxxxxxx> wrote: >>> Thanks for your input. So, you mean btt should not be piped with blkparse's >>> real time output. right? Because I have run btt offline and the only things >>> being piped are blktrace and blkparse which according to the manual page of >>> blktrace should not have any problem. >>> >>> >>> >>> On Wed, Apr 22, 2015 at 10:53 PM, Alireza Haghdoost <haghdoost@xxxxxxxxx> >>> wrote: >>>> >>>> btt timing is broken if you pipe real time output of blktrace outpu, >>>> verify that by examining blkparse output. You should be able to get >>>> what ever you want from blkparse. Run blktrace, capture trace files, >>>> then run blkparse offline and post process the human readble traces >>>> with your own scripting. >>>> >>>> On Wed, Apr 22, 2015 at 1:08 PM, Mansour Shafaei Moghaddam >>>> <mansoor.shafaei@xxxxxxxxx> wrote: >>>> > Running btt with -p option on the binary output of blkparse, I noticed >>>> > the following two weird cases and would appreciate it if anyone can >>>> > come up with an explanation for them. >>>> > >>>> > 1) In some IOs the time reported for C is earlier than for example >>>> > D!!!Here is an example: >>>> > >>>> > 8,16 : 159.151387465 Q 75313664+256 >>>> > 159.183107850 G 75313664+256 >>>> > 159.183108979 I 75313664+256 >>>> > 159.183109762 D 75313664+256 >>>> > 159.169694274 C 75313664+256 >>>> > >>>> > 2) In some others there are very very long (say hundreds of seconds) >>>> > delays between (Q I G D C) steps. Example of this case: >>>> > >>>> > 8,16 : 34386.651240899 Q 106649088+256 >>>> > 34386.651241669 G 106649088+256 >>>> > 34386.651243565 I 106649088+256 >>>> > 34386.651244370 D 106649088+256 >>>> > 35548.738015688 C 106649088+256 >>>> > -- >>>> > 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 >>> >>> -- 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
