Hi Mychaela, Thank you for the feedback. I was using it with "classic" Slackware and it was really annoying that I was getting this significant slowdown on Ubuntu.
-Serg On Fri, Jul 5, 2019 at 3:07 PM Mychaela Falconia < mychaela.falco...@gmail.com> wrote: > Serg wrote: > > > I was running loadtools on Ubuntu with FTDI USB to UART interface and > > noticed that increasing baudrate was giving just marginal load speed > > improvement. Quick analysis revealed that select() in the S-record echo > was > > signaled by the kernel with 10ms delay. I tried multiple baudrates and > > confirmed that that was pretty much constant. > > You must be seeing this behavior because you are running a too-new > Linux kernel version - it does not happen with more classic kernels. > I had implemented high baud rate support in loadtools back in 2013 and > have been enjoying the faster image transfers ever since then without > any problems. > > > Since we use Linux specific libserial now, I added one more kernel tweak, > > which may be not reproducible on other platforms. > > Because the problem only happens with too-new Linux kernel versions, > it is a Linux-specific problem, hence there is no problem with > addressing it only in the Linux-specific version of libserial. > > > Maybe there is a better > > place where we can set this flag, so here is a proof of concept. > > I will need to study the Linux kernel source and see exactly what this > ASYNC_LOW_LATENCY flag does before I can incorporate this change into > the official freecalypso-tools tree. I will try to find some time, > but I am not putting a high priority on it. > > > This makes an image load lighting fast compared to what I was getting > > before. So far no major problems observed. > > Hmm, transferring a ~2 MiB (in the case of firmwares) or 8 MiB (in the > case of forensic flash dumps) image over 812500 baud with each byte > sent as two hex characters is not what I would call lightning fast - > it is certainly tolerable, much more tolerable than doing the same > over 115200 baud, but I would not call it lightning fast by any means. > > Oh wait, you said it's lightning fast *compared to what you were > getting before*. Does that statement mean that you had never > experienced how well it works and has always worked with an older > host system? > > M~ > _______________________________________________ > Community mailing list > Community@freecalypso.org > https://www.freecalypso.org/mailman/listinfo/community > _______________________________________________ Community mailing list Community@freecalypso.org https://www.freecalypso.org/mailman/listinfo/community