When Blosc tries to compress a chunk, and the out buffer does not fit in the original size, a MEMCPY flag is activated, and compression restarts. And yes, that means that the prefilter (and hence, the computation) is executed twice.
This is not terribly bad, as the user can always disable compression manually, avoiding the overhead in these cases. However, it would be nice if we can make BTune to disable compression automatically in these cases.
When Blosc tries to compress a chunk, and the out buffer does not fit in the original size, a MEMCPY flag is activated, and compression restarts. And yes, that means that the prefilter (and hence, the computation) is executed twice.
This is not terribly bad, as the user can always disable compression manually, avoiding the overhead in these cases. However, it would be nice if we can make BTune to disable compression automatically in these cases.