Re: [Gems-users] question about XACT_LOG_BUFFER_SIZE parameter

[Jayaram Bobba <bobba@xxxxxxxxxxx>]

From the wiki,
*
XACT_LOG_BUFFER_SIZE*: (>=0) The size of a magical hardware log buffer. 
Used to perform 0-cycle restoration of memory values for any transaction 
having logs not exceeding this buffer size.
Basically, it allows zero-cycle aborts for small transactions.

You would need a bigger log buffer for transactions to be able to use 
it. In LogTM-SE, each transaction starts
off by writing a transaction header which itself is 68 bytes. So you 
would probably need something around 256 bytes
to be useful...

What kind of exception are you seeing when value is set to 1024?

Jayaram

cge@xxxxxxxx wrote:
> Hi,
>
> Does anyone know how can XACT_LOG_BUFFER_SIZE parameter enhance the  
> performance in
> MESI_CMP_filter_directory protocol.
> I tried to set the value to 16 or 32, and see no performance  
> difference in terms of cycles when running micro-program.
> Also when I set the parameter to a large value like 1024, an exception  
> will be thrown. Is there an allowable maximum value?
> Thanks,
> Cen
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