Pádraig Brady <[email protected]> writes: > This patch is in fact required with OpenZFS as my hunch was correct > that a zero length would be treated specially (even perhaps because > cp has used 0 for so long). With a specific length OpenZFS 2.2.2 > synchronously (decompresses and) populates the cache, which > defeats the subsequent copy offload. Details at: > https://github.com/coreutils/coreutils/issues/122 > > I'll apply the above, but also the attached more defensive patch, > to avoid fdadvise unless we really need it.
Interesting. Do you happen to have any performance benchmarks from when fadvise was added to 'cp'? I assumed that the impact of it would be minimal, but that report proves otherwise at least for ZFS. Collin
