Thus, users of HPF on the CRAY T3E are encouraged to leave the streams option off. The incoherence of the CRAY T3E memory streams can occur only in the specific cases described above. Not Using Streams. As pointed out earlier this is the rather obvious solution for many codes but also a quite undesirable solution for others. However, their use is not an all or nothing situation.
Users have simple, flexible control over the use of streams.
Turning streams on at an application's onset permits the streams to be active for the entire application. More relevantly, a programmer can safely choose to activate the streams hardware logic only in sections of code in which its performance boost is key and simultaneous cached and uncached memory references can not occur. Be aware that once a stream pattern has been recognized by the CRAY T3E support hardware, data will continue to flow through the streams buffers until the pattern is broken. Turning streams off once they have been turned on merely prevents the support logic from recognizing and establishing new streams. This function breaks the data flow from the streams buffers.