Re: [PATCH] perf trace: Add mmap alias for s390

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, May 31, 2017 at 01:35:57PM +0200, Jiri Olsa escreveu:
> The s390 architecture maps sys_mmap (nr 90) into sys_old_mmap.
> For this reason perf trace can't find the proper syscall event
> to get args format from and displays it wrong as 'continued'.
> 
> To fix that fill "alias" field with "old_mmap" for trace's mmap
> record to get the correct translation.

Ok, I'll add this, but at some point we'll need to do this by looking at
the perf.data header when cross-tracing on a non-live, perf.data based
setup.

- Arnaldo
 
> Before:
>      0.042 ( 0.011 ms): vest/43052 fstat(statbuf: 0x3ffff89fd90                ) = 0
>      0.042 ( 0.028 ms): vest/43052  ... [continued]: mmap()) = 0x3fffd6e2000
>      0.072 ( 0.025 ms): vest/43052 read(buf: 0x3fffd6e2000, count: 4096        ) = 6
> 
> After:
>      0.045 ( 0.011 ms): fstat(statbuf: 0x3ffff8a0930                           ) = 0
>      0.057 ( 0.018 ms): mmap(arg: 0x3ffff8a0858                                ) = 0x3fffd14a000
>      0.076 ( 0.025 ms): read(buf: 0x3fffd14a000, count: 4096                   ) = 6
> 
> Link: http://lkml.kernel.org/n/tip-3jrfsbpclxr1ftke2t9rpvy6@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/builtin-trace.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index d014350adc52..4b2a5d298197 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -681,6 +681,10 @@ static struct syscall_fmt {
>  	{ .name	    = "mlockall",   .errmsg = true,
>  	  .arg_scnprintf = { [0] = SCA_HEX, /* addr */ }, },
>  	{ .name	    = "mmap",	    .hexret = true,
> +/* The standard mmap maps to old_mmap on s390x */
> +#if defined(__s390x__)
> +	.alias = "old_mmap",
> +#endif
>  	  .arg_scnprintf = { [0] = SCA_HEX,	  /* addr */
>  			     [2] = SCA_MMAP_PROT, /* prot */
>  			     [3] = SCA_MMAP_FLAGS, /* flags */ }, },
> -- 
> 2.9.4