Finally CONFIG_HZ will take effects the scheduler Assuming you use default 32k clock source .from default kernel config and source .
And what I guess if you get delay about 10ms , you might get a delay schedule on 128HZ in default config So , If you use 1024HZ ,you can get about 1ms latency . And if the data is very frequency , fifo will not be the problem , what I just guess , if you only send several bytes in a peak time . fifo might be not enough to generate an interrupt . there is a 64 BYTES fifo in omap uart host controller . If this case just for bluetooth like skip fifo setting , just use 1024HZ ,it should be solve 2014-11-26 11:40 GMT+08:00 William Hermans <[email protected]>: > This is for UART ? There may even be a kernel boot config option that will > work with this hardware as well. Meaning: No need to recompile the kernel > to see if it works. > > On Tue, Nov 25, 2014 at 7:47 PM, liyaoshi <[email protected]> wrote: > >> So , can you try the 1024HZ for kernel scheduler ? >> And , do you have fflush () after you write uart ? >> >> 2014-11-25 23:51 GMT+08:00 Thomas O <[email protected]>: >> >>> Hey liyaoshi... I am running both uarts in 3,000,000 bytes per second! >>> It is the problem that i get long delys 10ms or more so it is not related >>> to speed but to latency. >>> Also it seems the kernel only copies from kernel space to the uart in >>> that same 10ms intervals. so it fills up the send queue for 10ms. >>> >>> On Tuesday, November 25, 2014 1:54:06 AM UTC, liyaoshi wrote: >>>> >>>> speed up to 921600bps or more if your remote uart can work >>>> >>>> 2014-11-24 19:17 GMT+08:00 Thomas O <[email protected]>: >>>> >>>>> Hi all i am writing some software using the OMAP_SERIAL drivers to >>>>> send and receive data from a c program (TERMIOS). >>>>> >>>>> I am seeing large delays 10ms ticks when sending and receiving data on >>>>> the UARTS >>>>> >>>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
