On Sat, Sep 16, 2017 at 04:51:00AM +0800, Sen Han wrote: > Thanks for your information. I want to use `ltrace` to find out if the > golang binary is using > the __vdso_clock_gettime_sym with CLOCK_MONOTONIC option for measuring time > interval. > > But it finally turns out currently the `ltrace` cannot works very well with > go built binaries on > vdso tracing. > > Is there some exist tools could trace the vdso call in golang? Or is there > any recommend methods > could achieve it on the runtime?
Go is free software so instead of trying to trace the binaries its compiler creates, you could just grep the runtime's source code. ;-) Especially given the fact that since version 1.5 Go is entirely written in Go (modulo some assembly code). I have just grepped the checkout of 1.9 for CLOCK_MONOTONIC, and I think devel/golang1.9/src/runtime/sys_linux_amd64.s is what you need. Look for the "nanotime" function. Note that at least on i386 and amd64, Linux maps the memory ranges containing the data related to date/time information into the address space of every process, so reading these data does not involves any syscalls -- merely direct reads of the data located at a certain memory address. IIRC, on Windows, a similar mechanism is used. Don't know about other supported kernels. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
