On Fri, Oct 31, 2014 at 12:35:18PM +0400, Antony Pavlov wrote:
On Thu, 30 Oct 2014 08:08:44 +0100 Gilles Chanteperdrix gilles.chanteperdrix@xenomai.org wrote:
On Wed, Oct 29, 2014 at 03:49:15PM +0100, Wolfgang Denk wrote:
Dear Madhu,
In message 23c3598d8b87452eb6a3d1f52afb8a34@SG2PR01MB0394.apcprd01.prod.exchangelabs.com you wrote:
We are looking for FTP client command in U-boot commands, So that, we can boot the O.S kernel-image through ftp-client(instead of tftpboot over network).
It would have been usful if you had told us whyyou thing the existing network protocols (TFTP, NFS) are not sufficient for your use cases?
Hi Wolfgang,
if you do not mind me interfering, I have started using HTTP with pxelinux recently, and I can answer this question: for large files (such as large initramfs files, which are practical nowadays since even some embedded boards have gigabytes of RAM), TCP based protocols are much, much faster than TFTP. That is because TFTP is a request/response protocol, which takes one round trip time for every packet asked. TCP based protocols, on the other hand benefit from sending several packets before getting an acknowledge, which means there is a "pipelining" effect.
Hmm.
low speed of TFTP protocol in U-boot is not a problem of TFTP protocol itself, but problem of TFTP protocol setup.
That is because you are running your tests with a network with a small round-trip time, and yes, if you augment the block size, you reduce the number of round-trips, so you reduce the duration. TCP on the other hand, will adapt the window size automatically and try and fill the pipe before waiting for an ack.