Re: [Discuss-gnuradio] Data lost whe using big file sources

[Martin Braun]

Hi Bogdan,

On Tue, Apr 10, 2012 at 03:48:11AM -0700, Bogdan Diaconescu wrote:
> Hello gnuradio fellows,
> 
> I have an issue that appears in all gnuradio versions I used lately (I 
> started with 3.3 and last week I updated to latest from git) and I thought I 
> should post here before allocating the time to look into it by myself.
> 
> I'm modifying a gnuradio block that is connected from python to 6 file 
> sources. Everything works fine as long as the files I'm using as source for 
> data are relatively small (30MB). When the files become large I see that the 
> data received in general_work() function is corrupted. It is not massively 
> corrupted but enough to screw my work.

I've seen this behaviour, too. My workaround was to use a throttle block
after noticing that my code works with USRPs, but not with files.
However, I never managed to trace the bug to the file source. Thanks for
this!

> Investigating the problem, I did a small test with having the 6 files filled 
> with known patterns and printing an error in the general_work() if what is 
> received is different. The result is that if I use files with sizes over 
> 100MB I see 50-80 errors in total.

Do you have errors, or are samples missing?

> Now, to unblock my work I did observe that if I insert some printing in 
> general_work() I will not get the errors. Going further, inserting a boost 
> delay of 100uS also solves the problem.
> 
> some more data: 
> 1. I know the new blocks should use work() instead of general_work() but is 
> it still supposed to work as long as I call consume_each(), right?

That should work since general_work() calls work() and then
consume_each(). Have a look at the code of gr_block (or was it
gr_basic_block?)

MB


-- 
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