Re: [Powertop] [PATCH 4/4] Add support for Intel GPU statistics
>
> + file.open("/sys/class/drm/card0/power/rc6_residency_ms", ios::in);
> +
> + if (file) {
> + handle_i965_gpu();
> + file.close();
> + }
> +
side note: just wonder how much C++ stream with its heavy buffering, etc. is slower
than stat(). I'll review and if it makes sense will probably prepare simple stat()
wrapper to lib.cpp
better to use access() than stat.
both have the fun of getting a bunch of low level system headers into C++
I'm sure that'll work most of the time, but for something as non-time critical as
this
I wonder how badly that is inviting trouble.
> +
> + if (line_nr == 0)
> + d = 100.0 - ratio * (rc6_after + rc6p_after + rc6pp_after - rc6_before -
rc6p_before - rc6pp_before);
> + if (line_nr == 1)
> + d = ratio * (rc6_after - rc6_before);
> + if (line_nr == 2)
> + d = ratio * (rc6p_after - rc6p_before);
> + if (line_nr == 3)
> + d = ratio * (rc6pp_after - rc6pp_before);
> + if (line_nr >= 4 || line_nr < 0)
> + return buffer;
> +
small side note /* someone will do it anyway :-) */:
how about
if (line_nr == 0)
d = 100.0 - ratio * (rc6_after + rc6p_after + rc6pp_after - rc6_before - rc6p_before -
rc6pp_before);
else if (line_nr == 1)
d = ratio * (rc6_after - rc6_before);
else if (line_nr == 2)
d = ratio * (rc6p_after - rc6p_before);
else if (line_nr == 3)
d = ratio * (rc6pp_after - rc6pp_before);
else if (line_nr >= 4 || line_nr < 0)
return buffer;
well last time I looked at the disassembly for such a case, this generated worse code.
I'll admit that that was about 2 gcc versions ago though.