On Tue, Aug 22, 2017 at 05:58:34PM +0000, Liang, Kan wrote:
> It looks there is still one room in cacheline 1.
> > So this is very unfortunate...
> >
> > struct perf_sample_data {
> > u64 addr; /* 0 8 */
> > struct perf_raw_record * raw; /* 8 8 */
> > struct perf_branch_stack * br_stack; /* 16 8 */
> > u64 period; /* 24 8 */
> > u64 weight; /* 32 8 */
> > u64 txn; /* 40 8 */
> > union perf_mem_data_src data_src; /* 48 8 */
> > u64 type; /* 56 8 */
You mean @type, right? That is unconditionally used by the output code.
> > /* --- cacheline 1 boundary (64 bytes) --- */
> > u64 ip; /* 64 8 */
> > struct {
> > u32 pid; /* 72 4 */
> > u32 tid; /* 76 4 */
> > } tid_entry; /* 72 8 */
> > u64 time; /* 80 8 */
> > u64 id; /* 88 8 */
> > u64 stream_id; /* 96 8 */
> > struct {
> > u32 cpu; /* 104 4 */
> > u32 reserved; /* 108 4 */
> > } cpu_entry; /* 104 8 */
> > struct perf_callchain_entry * callchain; /* 112 8 */
> > struct perf_regs regs_user; /* 120 16 */
> > /* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
> > struct pt_regs regs_user_copy; /* 136 168 */
> > /* --- cacheline 4 boundary (256 bytes) was 48 bytes ago --- */
> > struct perf_regs regs_intr; /* 304 16 */
> > /* --- cacheline 5 boundary (320 bytes) --- */
> > u64 stack_user_size; /* 320 8 */
> >
> > /* size: 384, cachelines: 6, members: 19 */
> > /* padding: 56 */
> > };
Now, I was hoping, that if you move the entire thing into generic code
(PPC also support PERF_SAMPLE_DATA) then we can avoid the init here and
rely on perf_sample_prepare().
