Hi Ben, I was having problems with what appears to be blocks of data being saved out of sync (tended to happen at decimation rates lower than 100) but I haven't had a chance to get to the root of this issue, my current line of thinking is that when blocks have a side effect the ordering isnt guarenteed.
I modified the USRP2 source to output a second stream of timestamps and found the problem by running a quick sanity check by saving to disk, then importing and checking if each timestamp is higher than the one preceding it. When using a C++ module (rather than a file sink) to check this everything seemed to be working as expected hence me thinking that it only occurs when the blocks output isnt limited to gnuradio. I might be completely wrong as I cant seem to find the code for the multi-threaded scheduler to try and work out whats going on, can anyone point me in the right direction? Cheers, Tim On Mon, Dec 7, 2009 at 6:18 PM, Ben Gear <bg...@dunelm.org.uk> wrote: > Hi all, > > Does anyone know if the scheduler is guaranteed to process blocks in > the correct order? For example, say you have a block with side > effects such as writing to a file, could it ever occur that the > scheduler is processing several work functions for the same block > concurrently in different threads, the threads execute at a different > rate and you end up with a file written out of order? In a similar > manner is accessing block member variables safe? For example I want > to write a 'latch' block that takes in and outputs bits. The output > will be low while the input is low until the first high bit is > received and then the output will remain high until it is reset. If I > store the latch state in a member variable is it guaranteed that when > the latch is triggered at a given sample number all the output sample > before hand will be 0 and all after will be 1? > > Many thanks, > > Ben Gear > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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