Hi Arun KS, Actually, i already saw this one and something similar were tested. I just trying to figure out the reasons why generic kernel layer (console_unlock) implemented in such way: i.e. why it accounts on immediate busyloop printing? Is it reliable to defer such printing to UART interrupts? Thank you. On Mon, 20 Jul 2015 09:34:16 +0530 Arun KS <getarunks@xxxxxxxxx> wrote: > Hello Alexander, > > On Sat, Jul 18, 2015 at 11:23 AM, Alexander <alexhoppus111@xxxxxxxxx> wrote: > > > > > Hi! > > When i checked how kernel printing works, i mentioned that it takes > > messages > > from log_buffer in console_unlock and gives it to call_console_drivers -> > > ... > > -> some uart bsp function. Basically, as i see this BSP realization tries > > to flush all message chars in busyloop ... so it waits until FIFO_NOT_FULL > > bit will > > be dropped by UART and it will be able to push the next byte. > > Basically, as i see userspace printing do something different. It puts > > N_FIFO_BYTES > > and exits, next, when FIFO will be freed - interrupt will be generated, and > > other characters will be put into UART FIFO. > > Can we do something similar for kernel printing? i.e. do not busyloop > > sending char > > after char, but put N_FIFO chars and flush other in interrupt. When panic > > will occur > > we can do busyloop printing again. Is it reliable? Suppose we have several > > cores. > > Thank you. > > > What about trying this patch, > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/kernel/printk/printk.c?id=5874af2003b1aaaa053128d655710140e3187226 > > Its not changing console printing through UART to interrupt mode. But > minimizes the time interrupts being disabled on printk(). > > Thanks, > Arun > > > > > > > -- > > Alexander <alexhoppus111@xxxxxxxxx> > > > > _______________________________________________ > > Kernelnewbies mailing list > > Kernelnewbies@xxxxxxxxxxxxxxxxx > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > -- Alexander <alexhoppus111@xxxxxxxxx> _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
