Messages in this thread | | | Subject | Re: [RFC v3][PATCH 0/2] Make ftrace able to trace function return | From | (Frank Ch. Eigler) | Date | Wed, 12 Nov 2008 15:44:03 -0500 |
| |
Frederic Weisbecker <fweisbec@gmail.com> writes:
> This patchset adds the ability for ftrace to trace the function even > on call time and on return time. So we can now measure the time of > execution of the most part of the functions inside the kernel with > ftrace. [...]
By the way, one extra complication you may need to deal with, beyond normal retprobes, is that by the time dyn-ftrace gets hold of the function entry, some part of the function prologue will have been executed. Because the mcount call/sequence is not the first instruction in the function body, is there a risk that the call frame cannot be reliably modified because of interference from those first few other instructions? Maybe on some architectures/optimization levels?
- FChE
| |