About the pv overhead, I sent a note to the pv author saying that on Linux at least the transfer function could take advantage of the splice system call. Splic

About the pv overhead, I sent a note to the pv author saying that on Linux at least the transfer function could take advantage of the splice system call. Splice "copies" data from one file descriptor to another file descriptor, avoiding having to copy the data from the kernel to userspace and back.