On Wed, Feb 13, 2019 at 9:47 PM Steven Rostedt <[email protected]> wrote: > > On Wed, 13 Feb 2019 14:19:01 +0800 > xiang xiao <[email protected]> wrote: > > > On Wed, Feb 13, 2019 at 3:46 AM Steven Rostedt <[email protected]> wrote: > > > > > > On Wed, 13 Feb 2019 02:11:05 +0800 > > > Xiang Xiao <[email protected]> wrote: > > > > > > > Because log may already add the timestamp sometime > > > > > > Can you be a bit more detailed on this. When and where does this > > > happen? > > > > Here is my case: > > 1.A small MCU(Cortex M4) in SoC run RTOS > > 2.RTOS append timestamp to log for the accurate timing > > 3.RTOS send log to Linux kernel when buffer exceed the threshold > > 4.Kernel call printk to dump the received buffer > > So I want that printk skip the timestamp here. > > > > > If anything, I would probably prefer that we export whether > > > time is being printed, and have the caller not print time if printk is > > > doing it already, than to add the complexity into printk itself. > > > > Actually, the timestamp of our initial implementation like your > > suggestion come from printk, > > but we found that timestamp from kernel isn't accurate as from RTOS > > due the buffer and IPC. > > > > If the timestamps are different, then you don't want to remove the > printk one. Otherwise you are going to have a confusion between your > added timestamp mixed in with the kernel's inaccurate timestamps. >
Here is a sample output with this patch: [ 10.991426] virtio_rpmsg_bus virtio1: rpmsg host is online [ 10.991443] remoteproc remoteproc1: registered virtio1 (type 7) [ 10.991450] remoteproc remoteproc1: remote processor f9210000.toppwr:sen-rproc is now up [ 10.993715] virtio_rpmsg_bus virtio1: creating channel rpmsg-ttySENSOR addr 0x1 [ 10.994606] virtio_rpmsg_bus virtio1: creating channel rpmsg-ttyGPS addr 0x2 [ 10.995236] virtio_rpmsg_bus virtio1: creating channel rpmsg-clk addr 0x3 [ 10.995702] virtio_rpmsg_bus virtio1: creating channel rpmsg-syslog addr 0x4 [ 10.996197] virtio_rpmsg_bus virtio1: creating channel rpmsg-rtc addr 0x5 [ 10.997297] virtio_rpmsg_bus virtio1: creating channel rpmsg-hostfs addr 0x6 [ 10.999842] virtio_rpmsg_bus virtio1: creating channel rpmsg-usrsock addr 0x7 [ 0.007680] sensor: NuttX sensor 7.28 e3c2ecb Feb 12 2019 16:53:49 arm song/banks ^^^^^^^^^^^^^ [ 11.918177] random: crng init done [ 12.567362] e2fsck: e2fsck 1.42.9 (28-Dec-2013) Without this patch: [ 10.991426] virtio_rpmsg_bus virtio1: rpmsg host is online [ 10.991443] remoteproc remoteproc1: registered virtio1 (type 7) [ 10.991450] remoteproc remoteproc1: remote processor f9210000.toppwr:sen-rproc is now up [ 10.993715] virtio_rpmsg_bus virtio1: creating channel rpmsg-ttySENSOR addr 0x1 [ 10.994606] virtio_rpmsg_bus virtio1: creating channel rpmsg-ttyGPS addr 0x2 [ 10.995236] virtio_rpmsg_bus virtio1: creating channel rpmsg-clk addr 0x3 [ 10.995702] virtio_rpmsg_bus virtio1: creating channel rpmsg-syslog addr 0x4 [ 10.996197] virtio_rpmsg_bus virtio1: creating channel rpmsg-rtc addr 0x5 [ 10.997297] virtio_rpmsg_bus virtio1: creating channel rpmsg-hostfs addr 0x6 [ 10.999842] virtio_rpmsg_bus virtio1: creating channel rpmsg-usrsock addr 0x7 [ 11.105345][ 0.007680] sensor: NuttX sensor 7.28 e3c2ecb Feb 12 2019 16:53:49 arm song/banks ^^^^^^^^^^^^^^^^^^^^^^^^^^ [ 11.918177] random: crng init done [ 12.567362] e2fsck: e2fsck 1.42.9 (28-Dec-2013) Which one do you think better? > -- Steve
