On Sat, Jul 11, 2020 at 7:37 PM jimlux <jim...@earthlink.net> wrote: > > You might want to look into one of the "real time" linux kernels or > other similar implementations - they might have "turned some of the > knobs" to improve the handling of device data.
The real time kernel primarily is about trying to get closer to making hard real time guarantees. To put a hard maximum on latencies. You can't really do that on Linux, but the real time patches made it better. Mostly this is about finding a place where X could not happen in time because the CPU was doing Y instead, and Y couldn't be interrupted. And find a way to interrupt Y so X doesn't have to wait. One of the biggest changes was to thread all interrupts. So that interrupts can be interrupted. If you are after low interrupt latency, this actually makes things worse. But it makes the worst case much better than before, at the expense of the average case. > > There is a reason why USB support was late in coming to Linux compared > to other devices. And there's a reason why everyone curses at serial I thought Linux had USB support quite early. I remember making a cable so I could test the USB 1.0 in my 430HX based computer, the first Intel chipset to have USB. I believe it didn't work properly, some kind of chipset problem. Unless it was the 430FX, it's been so long. Google tells me the 430FX didn't have USB. But I recall that Intel's first chipset with USB had a broken controller and the Ministry of Truth changed the advertising to "it never had USB." A check shows there was Linux USB support in 1996, while Windows didn't get it until 1997. There was a big redesign of the Linux USB stack by Linus in 1999. I remember things working quite a bit better after that was done. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.