If you use direct I/O to reduce CPU time, that means you are saving CPU via DMA. If you are using Java's heap though, you can kiss that goodbye.
That said, I'm surprised that the Atom can't keep up with magnetic disk unless you have a striped array. 100MB/s shouldn't be too taxing. Is it possible you're doing something wrong or your CPU is otherwise occupied? On Tue, Jan 4, 2011 at 9:58 AM, Da Zheng <zhen...@cs.jhu.edu> wrote: > The most important reason for me to use direct I/O is that the Atom > processor is too weak. If I wrote a simple program to write data to the > disk, CPU is almost 100% but the disk hasn't reached its maximal bandwidth. > When I write data to SSD, the difference is even larger. Even if the program > has saturated the two cores of the CPU, it cannot even get to the half of > the maximal bandwidth of SSD. > > I don't know how much benefit direct I/O can bring to the normal processor > such as Xeon, but I have a feeling I have to use direct I/O in order to have > good performance on Atom processors. > > Best, > Da -- Chris
