On Thu, 25 Jun 2020 09:53:15 -0400 (EDT) Mathieu Desnoyers <mathieu.desnoy...@efficios.com> wrote:
> ----- On Jun 25, 2020, at 9:44 AM, rostedt rost...@goodmis.org wrote: > > > From: "Steven Rostedt (VMware)" <rost...@goodmis.org> > > > > [ SEVEN YEAR PROBLEM SOLVED! ] > > > > Up until now, if an event is interrupted while it is recorded by an > > interrupt, and that interrupt records events, the time of those events will > > all be the same. This is because events only record the delta of the time > > since the previous event (or beginning of a page), and to handle updating > > the time keeping for that of nested events is extremely racy. After years of > > thinking about this and several failed attempts, I finally have a solution > > to solve this puzzle. > > Out of curiosity, considering that LTTng has solved this problem 10+ years ago > with a simpler concurrency-friendly time-stamping model, why not simply use it > rather than add complexity to the current ftrace timestamp scheme ? Because it requires updating all the tools that read this from user space. I found a solution that works, so why change it and cause the backward compatibility pain now? -- Steve
