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?
Thanks.
PS:
With your information then I tried again:
$ cat hi.go
package main
import (
"fmt"
"time"
)
func main() {
fmt.Println("hi!")
start := *time.Now()*
t := time.Now()
fmt.Println(t.Sub(start))
}
$ CGO_ENABLED=0 go build -a -x -*linkshared* hi.go
...
$ *ldd hi*
linux-vdso.so.1 => (0x00007ffe96de7000)
libc.so.6 => /lib64/libc.so.6 (0x00007f721e492000)
/lib64/ld-linux-x86-64.so.2 (0x00007f721e85f000)
$ ltrace -s 1000 -tttTf ./hi
[pid 2305] 1505506857.418373 __libc_start_main(0x4bbcb0, 1, 0x7fff8d799738,
0x51a270hi!
540ns
<no return ...>
[pid 2306] 1505506857.440419 +++ exited (status 0) +++
[pid 2307] 1505506857.440451 +++ exited (status 0) +++
[pid 2308] 1505506857.440946 +++ exited (status 0) +++
[pid 2305] 1505506857.440972 +++ exited (status 0) +++
$ *readelf -r hi*
Relocation section '.rela.dyn' at offset 0x65650 contains 2 entries:
Offset Info Type Sym. Value Sym. Name +
Addend
0000007e1fe8 000100000006 R_X86_64_GLOB_DAT 0000000000000000
__gmon_start__ + 0
0000007e1ff0 115e00000012 R_X86_64_TPOFF64 0000000000000000 runtime.tlsg
+ 0
Relocation section '.rela.plt' at offset 0x65680 contains 2 entries:
Offset Info Type Sym. Value Sym. Name +
Addend
0000007e1fd8 000100000007 R_X86_64_JUMP_SLO 0000000000000000
__gmon_start__ + 0
0000007e1fe0 000300000007 R_X86_64_JUMP_SLO 0000000000000000
*__libc_start_main
+ 0*
On Fri, Sep 15, 2017 at 9:48 PM, Konstantin Khomoutov <kos...@bswap.ru>
wrote:
> On Fri, Sep 15, 2017 at 04:09:24AM -0700, nehs...@gmail.com wrote:
>
> > Hi, I just found `ltrace` would yield "Couldn't find .dynsym or .dynstr
> in
> > "/proc/*/exe" with executable binary generated by "go build *.go".
> >
> > Is there any options in `go build` could solve this problem?
> >
> > Thanks a lot.
> >
> > PS:
> > $go version
> > go version go1.9 linux/amd64
> > $ cat hi.go
> > package main
> >
> >
> > import "fmt"
> >
> >
> > func main() {
> > fmt.Println("hi!")
> > }
> > $ go build hi.go
> > $ ltrace ./hi
> > Couldn't find .dynsym or .dynstr in "/proc/`*`/exe"
>
> From the description of the ltrace's Debian package, I gather that
>
> | ltrace is a debugging program which runs a specified command until it
> | exits. While the command is executing, ltrace intercepts and records
> | the dynamic library calls which are called by
> | the executed process and the signals received by that process.
> | It can also intercept and print the system calls executed by the program.
>
> The Go compiler (of the "gc" suite you seem to use) generates statically
> compiled executable which link with no dynamic libraries (at least on
> Linux/amd64, with the reasonably current Go versions).
>
> Supposedly this explains why you don't see the those ".dyn*" sections in
> the generated ELF file.
>
> So what is your goal, exactly? What do you want to achieve?
>
>
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