Hi Konstantin, I use the same code already in fio for stopping. The do_dry_run() uses the same while-do construct as in do_io(). After the do_dry_run() completes, the do_verify() will verify the io units that where logged using log_io_piece(). On a related subject: I found an unexpected behavior with the current version (2.1.2) of fio when specifying an iodepth > 1 (with a random workload and libaio io engine and the default random generator and not using a random map). An example job that produces the behavior is attached. When a job like that is run, do_io() will perform extra io in the amount of the extra io that was allowed to accumulate in the queue. In other words, if iodepth=2, fio will do 1 extra io. I will send a different patch for this. Regards, Juan On Fri, Sep 13, 2013 at 10:53 PM, Ruvinsky, Konstantin <Konstantin.Ruvinsky@xxxxxxx> wrote: > Hi Juan, > > I removed the second question - understood what you meant. > > Regards > Konstantin > > -----Original Message----- > From: Ruvinsky, Konstantin > Sent: Saturday, September 14, 2013 8:34 AM > To: 'Juan Casse'; 'fio@xxxxxxxxxxxxxxx' > Subject: RE: [PATCH V2] Adds verify_only option. > > Hi Juan, > > Two questions: > 1. How fio knows where is the last block (where to stop verification run)? Please let me know if I understand it correctly: because lfsr runs without duplicated blocks then number of iterations is device_size/block_size. > 2. You wrote: "The verify_only option performs only verification (reads performed in do_verify()) and no read or write workload". But for verification, even if you made dry run till the end, you need to read. I don't follow. > > Regards > Konstantin > > -----Original Message----- > From: fio-owner@xxxxxxxxxxxxxxx [mailto:fio-owner@xxxxxxxxxxxxxxx] On Behalf Of Juan Casse > Sent: Friday, September 13, 2013 11:07 PM > To: Jens Axboe > Cc: Grant Grundler; fio@xxxxxxxxxxxxxxx; Juan Casse > Subject: [PATCH V2] Adds verify_only option. > > The verify_only option performs only verification (reads performed in do_verify()) and no read or write workload. The goal is to verify previously written meta data quickly and be able to detect stale data. > Without this option, fio does not detect stale data from previous fio runs---only data corruption of "misplaced" data. > > This option replays the specified write workload sequence in order to compute the "generation number" (using numberio field) for each block header that was written in a previous fio run. The numberio field is used to detect stale data. do_verify() checks numberio only in the last iteration, after the correct numberio for each block has been computed.
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