Zing has the option to do just that on systems which reliably support it (-XX:+UseRdtsc IIRC). So yes it can be done, and is sometimes even the right thing to do.
On Tue, Apr 30, 2019 at 7:50 AM dor laor <dor.l...@gmail.com> wrote: > It might be since in the past many systems did not have a stable rdtsc and > thus if the instruction is executed > on different sockets it can result in wrong answers and negative time. > Today most systems do have a stable tsc > and you can verify it from userspace/java too. > I bet it's easy to google the reason > > On Mon, Apr 29, 2019 at 2:36 PM 'Carl Mastrangelo' via mechanical-sympathy > <mechanical-sympathy@googlegroups.com> wrote: > >> This may be a dumb question, but why (on Linux) is System.nanotime() a >> call out to clock_gettime? It seems like it could be inlined by the JVM, >> and stripped down to the rdtsc instruction. From my reading of the vDSO >> source for x86, the implementation is not that complex, and could be copied >> into Java. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "mechanical-sympathy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to mechanical-sympathy+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to the Google Groups > "mechanical-sympathy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to mechanical-sympathy+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "mechanical-sympathy" group. To unsubscribe from this group and stop receiving emails from it, send an email to mechanical-sympathy+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
