On 07/19/2017 08:28 AM, Thomas Gleixner wrote: > On Wed, 19 Jul 2017, Prarit Bhargava wrote: >> On 07/19/2017 03:23 AM, Thomas Gleixner wrote: >>> There is another option to remedy this and the dmesg tooling issues: >>> >>> Instead of switching the time stamps in dmesg to a different clock we might >>> as well have an optional secondary timestamp. So instead of: >>> >>> [ 341.590930] wlan0: associated >>> >>> you would get: >>> >>> [ 341.590930] [ sec.usec] wlan0: associated >>> >>> where the second time stamp would be CLOCK_REALTIME/BOOTTIME. >>> >>> That should also solve Prarits problem, hmm? >> >> It would but I would prefer a single time stamp be printed than two. I think >> two timestamps is adding confusion to the output from a end-users point of view. > > Fair enough. I came up with that idea when I looked at the old thread. The > discussion about tools (e.g. dmesg) dried out at some point and looked > unresolved. tglx, There were two outstanding issues with my patchset. The first, as you mention above, is the issue with tooling. I will handle the chicken-and-egg issue with the kernel modification and tooling. I will post patches for dmesg & systemd once the kernel patchset lands in a "next" tree; other tools will have to be patched as we find them. The second issue is a sysfs stability and output issue that I have a question on. Since I'm changing the value of print.time from a bool to an int, the output of /sys/modules/printk/parameters/time would change from Y/N to 0-3. The file is not listed in Documentation/ABI/stable so I think I can change it. Can you confirm that this is the case? I wary of changing anything under sysfs and I'm not sure who else would know if I can change the output of that file. If it is the case that the output can be changed, then I'm going to suggest that we allow, for example, human-readable format "printk.time=monotonic" along with "printk.time=2" as kernel parameters. I would also like your thoughts on that idea. If the file cannot be changed I will have to add an additional module parameter to printk. Does "timestamp" sound okay to you? I will go with whatever you suggest. Thanks, P.
