Re: [PATCH V6 01/17] perf, x86: Reduce lbr_sel_map size

Peter Zijlstra
2014-10-24T09:39:38Z

On Sun, Oct 19, 2014 at 05:54:56PM -0400, Kan Liang wrote:

This should still very much have:

From: Yan, Zheng <zheng.z.yan@intel.com>

Seeing how you did not write this patch, probably true for all the
others too, although I've not checked yet.

> The index of lbr_sel_map is bit value of perf branch_sample_type.
> PERF_SAMPLE_BRANCH_MAX is 1024 at present, so each lbr_sel_map uses
> 4096 bytes. By using bit shift as index, we can reduce lbr_sel_map
> size to 40 bytes. This patch defines 'bit shift' for branch types,
> and use 'bit shift' to define lbr_sel_maps.
>
> Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
> Signed-off-by: Kan Liang <kan.liang@intel.com>
> Reviewed-by: Stephane Eranian <eranian@google.com>
> ---