Hi, >> Vs. goal 2: UBIFS write speed is about 70MiB/second, because of >> the write-back support. IOW, UBIFS is similar to traditional FSes >> like ext2, which have internal buffers and make writes fast. To >> compare, JFFS2 write speed on XO is about 1.3 MiB/s, because it is >> always synchronous.
> I'm curious how you measured this, as the underlying hardware only > supports a max. transfer rate of around 20 MiB/s... The "write-back" support mentioned above is describing a situation where we write to a kernel cache and defer writes to the hardware until later. JFFS2 does not do this, hence never getting *filesystem* write speeds that are above the hardware limitation. The 70MiB/second figure describes writes as seen coming into the UBIFS filesystem, which are not bound to the max. transfer rate of the hardware. In short, the write speed for a filesystem does not have to be bound by the underlying speed of flushing write buffers to hardware; in most modern filesystem it isn't, although in JFFS2 it is. - Chris. -- Chris Ball <[EMAIL PROTECTED]> _______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel