Re: [PATCH V2 1/7] perf, x86: Reduce lbr_sel_map size

From: Stephane Eranian
Date: Wed Oct 24 2012 - 03:28:26 EST

On Wed, Oct 24, 2012 at 7:59 AM, Yan, Zheng <zheng.z.yan@xxxxxxxxx> wrote:
> From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
>
> The index of lbr_sel_map is bit value of perf branch_sample_type.
> By using bit shift as index, we can reduce lbr_sel_map size.
>
> Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
> ---
> arch/x86/kernel/cpu/perf_event.h | 4 +++
> arch/x86/kernel/cpu/perf_event_intel_lbr.c | 50 ++++++++++++++----------------
> include/uapi/linux/perf_event.h | 42 +++++++++++++++++--------
> 3 files changed, 56 insertions(+), 40 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
> index d3b3bb7..ea6749a 100644
> --- a/arch/x86/kernel/cpu/perf_event.h
> +++ b/arch/x86/kernel/cpu/perf_event.h
> @@ -412,6 +412,10 @@ struct x86_pmu {
> struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr);
> };
>
> +enum {
> + PERF_SAMPLE_BRANCH_SELECT_MAP_SIZE = PERF_SAMPLE_BRANCH_MAX_SHIFT,
> +};
> +
What's the point on the extraneous definition?

> #define x86_add_quirk(func_) \
> do { \
> static struct x86_pmu_quirk __quirk __initdata = { \
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
> index 31fe046..7d9ae5f 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
> @@ -61,10 +61,6 @@ enum {
> #define LBR_FROM_FLAG_INTX (1ULL << 62)
> #define LBR_FROM_FLAG_ABORT (1ULL << 61)
>
> -#define for_each_branch_sample_type(x) \
> - for ((x) = PERF_SAMPLE_BRANCH_USER; \
> - (x) < PERF_SAMPLE_BRANCH_MAX; (x) <<= 1)
> -
> /*
> * x86control flow change classification
> * x86control flow changes include branches, interrupts, traps, faults
> @@ -378,14 +374,14 @@ static int intel_pmu_setup_hw_lbr_filter(struct perf_event *event)
> {
> struct hw_perf_event_extra *reg;
> u64 br_type = event->attr.branch_sample_type;
> - u64 mask = 0, m;
> - u64 v;
> + u64 mask = 0, v;
> + int i;
>
> - for_each_branch_sample_type(m) {
> - if (!(br_type & m))
> + for (i = 0; i < PERF_SAMPLE_BRANCH_SELECT_MAP_SIZE; i++) {

Why not just define for_each_branch_shift()?

> + if (!(br_type & (1U << i)))
> continue;
>
> - v = x86_pmu.lbr_sel_map[m];
> + v = x86_pmu.lbr_sel_map[i];
> if (v == LBR_NOT_SUPP)
> return -EOPNOTSUPP;
>
> @@ -631,33 +627,33 @@ intel_pmu_lbr_filter(struct cpu_hw_events *cpuc)
> /*
> * Map interface branch filters onto LBR filters
> */
> -static const int nhm_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX] = {
> - [PERF_SAMPLE_BRANCH_ANY] = LBR_ANY,
> - [PERF_SAMPLE_BRANCH_USER] = LBR_USER,
> - [PERF_SAMPLE_BRANCH_KERNEL] = LBR_KERNEL,
> - [PERF_SAMPLE_BRANCH_HV] = LBR_IGN,
> - [PERF_SAMPLE_BRANCH_ANY_RETURN] = LBR_RETURN | LBR_REL_JMP
> - | LBR_IND_JMP | LBR_FAR,
> +static const int nhm_lbr_sel_map[PERF_SAMPLE_BRANCH_SELECT_MAP_SIZE] = {
> + [PERF_SAMPLE_BRANCH_ANY_SHIFT] = LBR_ANY,
> + [PERF_SAMPLE_BRANCH_USER_SHIFT] = LBR_USER,
> + [PERF_SAMPLE_BRANCH_KERNEL_SHIFT] = LBR_KERNEL,
> + [PERF_SAMPLE_BRANCH_HV_SHIFT] = LBR_IGN,
> + [PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT] = LBR_RETURN | LBR_REL_JMP
> + | LBR_IND_JMP | LBR_FAR,
> /*
> * NHM/WSM erratum: must include REL_JMP+IND_JMP to get CALL branches
> */
> - [PERF_SAMPLE_BRANCH_ANY_CALL] =
> + [PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT] =
> LBR_REL_CALL | LBR_IND_CALL | LBR_REL_JMP | LBR_IND_JMP | LBR_FAR,
> /*
> * NHM/WSM erratum: must include IND_JMP to capture IND_CALL
> */
> - [PERF_SAMPLE_BRANCH_IND_CALL] = LBR_IND_CALL | LBR_IND_JMP,
> + [PERF_SAMPLE_BRANCH_IND_CALL_SHIFT] = LBR_IND_CALL | LBR_IND_JMP,
> };
>
> -static const int snb_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX] = {
> - [PERF_SAMPLE_BRANCH_ANY] = LBR_ANY,
> - [PERF_SAMPLE_BRANCH_USER] = LBR_USER,
> - [PERF_SAMPLE_BRANCH_KERNEL] = LBR_KERNEL,
> - [PERF_SAMPLE_BRANCH_HV] = LBR_IGN,
> - [PERF_SAMPLE_BRANCH_ANY_RETURN] = LBR_RETURN | LBR_FAR,
> - [PERF_SAMPLE_BRANCH_ANY_CALL] = LBR_REL_CALL | LBR_IND_CALL
> - | LBR_FAR,
> - [PERF_SAMPLE_BRANCH_IND_CALL] = LBR_IND_CALL,
> +static const int snb_lbr_sel_map[PERF_SAMPLE_BRANCH_SELECT_MAP_SIZE] = {
> + [PERF_SAMPLE_BRANCH_ANY_SHIFT] = LBR_ANY,
> + [PERF_SAMPLE_BRANCH_USER_SHIFT] = LBR_USER,
> + [PERF_SAMPLE_BRANCH_KERNEL_SHIFT] = LBR_KERNEL,
> + [PERF_SAMPLE_BRANCH_HV_SHIFT] = LBR_IGN,
> + [PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT] = LBR_RETURN | LBR_FAR,
> + [PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT] = LBR_REL_CALL | LBR_IND_CALL
> + | LBR_FAR,
> + [PERF_SAMPLE_BRANCH_IND_CALL_SHIFT] = LBR_IND_CALL,
> };
>
> /* core */
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index d1ffdb6..4a735be 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -148,20 +148,36 @@ enum perf_event_sample_format {
> * The branch types can be combined, however BRANCH_ANY covers all types
> * of branches and therefore it supersedes all the other types.
> */
> +enum perf_branch_sample_type_shift {
> + PERF_SAMPLE_BRANCH_USER_SHIFT = 0, /* user branches */
> + PERF_SAMPLE_BRANCH_KERNEL_SHIFT = 1, /* kernel branches */
> + PERF_SAMPLE_BRANCH_HV_SHIFT = 2, /* hypervisor branches */
> +
> + PERF_SAMPLE_BRANCH_ANY_SHIFT = 3, /* any branch types */
> + PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT = 4, /* any call branch */
> + PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT = 5, /* any return branch */
> + PERF_SAMPLE_BRANCH_IND_CALL_SHIFT = 6, /* indirect calls */
> + PERF_SAMPLE_BRANCH_ABORT_SHIFT = 7, /* transaction aborts */
> + PERF_SAMPLE_BRANCH_INTX_SHIFT = 8, /* in transaction */
> + PERF_SAMPLE_BRANCH_NOTX_SHIFT = 9, /* not in transaction */
> +
> + PERF_SAMPLE_BRANCH_MAX_SHIFT, /* non-ABI */
> +};
> +
> enum perf_branch_sample_type {
> - PERF_SAMPLE_BRANCH_USER = 1U << 0, /* user branches */
> - PERF_SAMPLE_BRANCH_KERNEL = 1U << 1, /* kernel branches */
> - PERF_SAMPLE_BRANCH_HV = 1U << 2, /* hypervisor branches */
> -
> - PERF_SAMPLE_BRANCH_ANY = 1U << 3, /* any branch types */
> - PERF_SAMPLE_BRANCH_ANY_CALL = 1U << 4, /* any call branch */
> - PERF_SAMPLE_BRANCH_ANY_RETURN = 1U << 5, /* any return branch */
> - PERF_SAMPLE_BRANCH_IND_CALL = 1U << 6, /* indirect calls */
> - PERF_SAMPLE_BRANCH_ABORT = 1U << 7, /* transaction aborts */
> - PERF_SAMPLE_BRANCH_INTX = 1U << 8, /* in transaction (flag) */
> - PERF_SAMPLE_BRANCH_NOTX = 1U << 9, /* not in transaction (flag) */
> -
> - PERF_SAMPLE_BRANCH_MAX = 1U << 10, /* non-ABI */
> + PERF_SAMPLE_BRANCH_USER = 1U << PERF_SAMPLE_BRANCH_USER_SHIFT,
> + PERF_SAMPLE_BRANCH_KERNEL = 1U << PERF_SAMPLE_BRANCH_KERNEL_SHIFT,
> + PERF_SAMPLE_BRANCH_HV = 1U << PERF_SAMPLE_BRANCH_HV_SHIFT,
> +
> + PERF_SAMPLE_BRANCH_ANY = 1U << PERF_SAMPLE_BRANCH_ANY_SHIFT,
> + PERF_SAMPLE_BRANCH_ANY_CALL = 1U << PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT,
> + PERF_SAMPLE_BRANCH_ANY_RETURN = 1U << PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT,
> + PERF_SAMPLE_BRANCH_IND_CALL = 1U << PERF_SAMPLE_BRANCH_IND_CALL_SHIFT,
> + PERF_SAMPLE_BRANCH_ABORT = 1U << PERF_SAMPLE_BRANCH_ABORT_SHIFT,
> + PERF_SAMPLE_BRANCH_INTX = 1U << PERF_SAMPLE_BRANCH_INTX_SHIFT,
> + PERF_SAMPLE_BRANCH_NOTX = 1U << PERF_SAMPLE_BRANCH_NOTX_SHIFT,
> +
> + PERF_SAMPLE_BRANCH_MAX = 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT,
> };
>
> #define PERF_SAMPLE_BRANCH_PLM_ALL \
> --
> 1.7.11.7
>
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