Ingo Schwarze <schwa...@usta.de> wrote: > Hi, > > i wonder whether there is a layering violation going on here. > > From the user perspective, whether an API call is a syscall or a > mere library function doesn't make any difference, it's an > implementation detail.
>From the developer's perspective it is a HUGE DEAL, because ktrace now doesn't show calls to gettimeofday / clock_gettime calls in the code most often traced (event loops). > API calls have often moved from being library > functions to syscall and vice versa, witnessed by the blurry line > between sections 2 and 3 in the manual (which is not a problem at > all). When that happened, they remained visible. This time, they become invisible. o you say the user wants to see whether their program calls > some time-related API functions, and in the past, ktrace was useful > for that. On a machine where syscalls for the purpose are no longer > needed due to pirofti@'s optimization, does it really make sense to > force useless syscalls just to be able to see the API calls in ktrace? > Wouldn't it make more sense to instead simply use ltrace(1), which IIUC > is intended for just that purpose, tracing API calls? There are many circumstances where ltrace is not suitable. It exposes the wrong interface, and fails to show the parameters in the expected fashion. > Someone said setting up ltrace(1) is kind of harder, while ktrace(1) > is very easy to use (i can confirm the latter, i use ktrace regularly). > So maybe the real problem is to make sure ltrace(1) is about as easy > to use as ktrace(1)? (Not sure what exactly the problem(s) with ltrace > usability are, if any, i didn't use it much so far.) I don't want to see the layers of functions, which means I don't want to use ltrace. I want ktrace to be useful. > It feels odd that a user would fiddle with the internal way how API > calls are implemented, in particular using something as scary as > environment variables, just to *inspect* what their program is doing... We fiddle with programs all the time, to inspect them. We add debug printf's! How can doing this in a more subtle way be harmful?
