[Barrelfish-users] Corruption sending buffer

[Zeus Gómez Marmolejo]

Ok,

I've simplified the example even more. Now, there is no buffer sent. Only a
uint32_t as a parameter of the message handler. Each time this integer is
being incremented by 1. This keeps going till it aborts when the integer
received by the second core is not what it should be.

As before, there are 2 cores, one sending and the other receiving with 1
thread per core. x86_64 is the architecture.

This error prevents my benchmarks from running as I'm sending a lot of
messages from one node to another and at some point it aborts because the
gasnet handler index is not correct.

Thanks for your help!

zeus.

El 17 de enero de 2012 15:06, Zeus Gómez Marmolejo <zeus.gomez at bsc.es>escribió:

> Hi Andrew,
>
> El 16 de enero de 2012 20:58, Baumann Andrew <andrewb at inf.ethz.ch>escribió:
>
>  Hi Zeus,****
>>
>> ** **
>>
>> At first look your program appears to be correct if sizeof(unsigned) == 4
>> on both source and destination. Although sending 4kB buffers through the
>> IDC system in this way is madness, it should work.****
>>
>> **
>>
>
> Yes, I forgot to say that the architecture I was running is x86_64.
>
>
>
>>  **
>>
>> Unfortunately I’m not in a good position to run this right now (… it’s a
>> long story involving snow and an out-of-date QEMU). When it fails, is the
>> incorrect value one from the previous iteration, or is it garbage?****
>>
>> **
>>
>
> The incorrect value is 0 almost all the time is failing.
>
>
>> **
>>
>> BTW, there is a minor use-after-free bug in your debug_printf() in the
>> receive handler.****
>>
>> **
>>
>
> You are right, but placing the debug_printf() before the free() doesn't
> make the error go away.
>
>
>> **
>>
>> Andrew****
>>
>> ** **
>>
>> *From:* Zeus Gómez Marmolejo [mailto:zeus.gomez at bsc.es]
>> *Sent:* Monday, 16 January 2012 11:39
>> *To:* barrelfish-users at lists.inf.ethz.ch
>> *Subject:* [Barrelfish-users] Corruption sending buffer****
>>
>> ** **
>>
>> Dear Barrelfish developers,****
>>
>> ** **
>>
>> I believe that I've found a bug in the message passing interface when a
>> buffer is sent between two endpoints. I would like you to have a look at
>> this example I'm sending to you. You can copy it to the folder
>> "usr/tests/idctest" of the latest version of the public repository. It
>> should build correctly.****
>>
>> ** **
>>
>> This is a very simple example: it has 2 cores, with one thread per core.
>> Only one core is sending a message to the other core. The message is a
>> simple buffer of 1024 unsigned integers where the first integer and the
>> last one is the same, it's incremented in each message sent. The message
>> handler on the receiver is just checking that the first and the last
>> integer of the buffer are the same.****
>>
>> ** **
>>
>> The application keeps running until it finds that the two integers
>> differ. This means that the buffer has been sent incorrectly. I've tested
>> this in qemu and in a real machine and after a while the program aborts
>> because of a corrupt buffer. In both systems, the error happens before 2
>> minutes approx.****
>>
>> ** **
>>
>> Can you have a look at this example and check whether I'm doing something
>> wrong?
>> ****
>>
>> ** **
>>
>> Many thanks!!****
>>
>> ** **
>>
>> ** **
>>
>> --
>> Zeus Gómez Marmolejo
>> Barcelona Supercomputing Center
>> PhD student
>> http://www.bsc.es
>>
>> ****
>>
>
>
>
> --
> Zeus Gómez Marmolejo
> Barcelona Supercomputing Center
> PhD student
> http://www.bsc.es
>
>
>


-- 
Zeus Gómez Marmolejo
Barcelona Supercomputing Center
PhD student
http://www.bsc.es
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