On 10.05.21 16:57, Shivank Garg wrote:
Hi Everyone! I want to profile the time taken to execute the __alloc_pages_nodemask for different linux configurations/parameters. To measure the execution time, I use the ktime_get() apis. I get the ktime_get() on the top, and I want to do ktime_sub(ktime_get(),ktime) and record it in a tracepoint.
Don't tracepoints already record a timestamp? It's bee a while since I worked with tracepoints ...
However, the patch on implementation prevents the kernel from booting up. I debugged the bug to find out that the issue recurs on adding ktime_get() inside the __alloc_pages_nodemask path. So, that the kernel fails to boot up ( and show the blank screen without any logs ) I'm using the Linux kernel 5.6.13 (5821a5593fa9f28eb6fcc95c35d00454d9bb8624)
Are you maybe calling ktime_get() too early during boot, where some subsystems are just about to be brought up?
Is it an expected behavior? or a BUG? Has anyone else faced the same issue? Can you please suggest, what would be a good way to measure execution time for page allocation (if not ktime_get)
I could have sworn ordinary tracepoints would already give you a timestamp ...
-- Thanks, David / dhildenb
