Umm. cpu_clock() isn't even cross-cpu synchronized, and has actually
thrown away all the information that can make it so, afaik. At least the
comments say "never more than 2 jiffies difference"). You do realize that
if you want to order events across CPU's, we're not talking about
"jiffies" here, we're talking about 50-100 CPU _cycles_.
You also ignore the early trace issues, and have apparently not used it
for FTRACE. You also ignore the fact that without TSC, it goes into the
same "crap mode" that is appropriate for the scheduler, but totally
useless for tracing.
IOW, you say that I call your arguments BS without telling you why, but
that's just because you apparently cut out all the things I _did_ tell you
why about!
The fact is, people who do tracing will want better clocks - and have
gotten with other infrastructure - than you have apparently cared about.
You've worried about scheduler tracing, and you seem to want to just have
everybody use a simple but known-bad approach that was good enough for
you.
Linus
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