lkml.org 
[lkml]   [2017]   [Apr]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v6 1/7] perf/core: Define the common branch type classification
    Date
    It is often useful to know the branch types while analyzing branch
    data. For example, a call is very different from a conditional branch.

    Currently we have to look it up in binary while the binary may later
    not be available and even the binary is available but user has to take
    some time. It is very useful for user to check it directly in perf
    report.

    Perf already has support for disassembling the branch instruction
    to get the x86 branch type.

    To keep consistent on kernel and userspace and make the classification
    more common, the patch adds the common branch type classification
    in perf_event.h.

    PERF_BR_NONE : unknown
    PERF_BR_JCC : conditional jump
    PERF_BR_JMP : jump
    PERF_BR_IND_JMP : indirect jump
    PERF_BR_CALL : call
    PERF_BR_IND_CALL : indirect call
    PERF_BR_RET : return
    PERF_BR_SYSCALL : syscall
    PERF_BR_SYSRET : syscall return
    PERF_BR_IRQ : hw interrupt/trap/fault
    PERF_BR_INT : sw interrupt
    PERF_BR_IRET : return from interrupt
    PERF_BR_FAR_BRANCH: not generic far branch type

    The patch also adds a new field type (4 bits) in perf_branch_entry
    to record the branch type.

    Since the disassembling of branch instruction needs some overhead,
    a new PERF_SAMPLE_BRANCH_TYPE_SAVE is introduced to indicate if it
    needs to disassemble the branch instruction and record the branch
    type.

    Change log
    ----------

    v6: Not changed.

    v5: Not changed. The v5 patch series just change the userspace.

    v4: Comparing to previous version, the major changes are:

    1. Remove the PERF_BR_JCC_FWD/PERF_BR_JCC_BWD, they will be
    computed later in userspace.

    2. Remove the "cross" field in perf_branch_entry. The cross page
    computing will be done later in userspace.

    Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
    ---
    include/uapi/linux/perf_event.h | 29 ++++++++++++++++++++++++++++-
    tools/include/uapi/linux/perf_event.h | 29 ++++++++++++++++++++++++++++-
    2 files changed, 56 insertions(+), 2 deletions(-)

    diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
    index d09a9cd..69af012 100644
    --- a/include/uapi/linux/perf_event.h
    +++ b/include/uapi/linux/perf_event.h
    @@ -174,6 +174,8 @@ enum perf_branch_sample_type_shift {
    PERF_SAMPLE_BRANCH_NO_FLAGS_SHIFT = 14, /* no flags */
    PERF_SAMPLE_BRANCH_NO_CYCLES_SHIFT = 15, /* no cycles */

    + PERF_SAMPLE_BRANCH_TYPE_SAVE_SHIFT = 16, /* save branch type */
    +
    PERF_SAMPLE_BRANCH_MAX_SHIFT /* non-ABI */
    };

    @@ -198,9 +200,32 @@ enum perf_branch_sample_type {
    PERF_SAMPLE_BRANCH_NO_FLAGS = 1U << PERF_SAMPLE_BRANCH_NO_FLAGS_SHIFT,
    PERF_SAMPLE_BRANCH_NO_CYCLES = 1U << PERF_SAMPLE_BRANCH_NO_CYCLES_SHIFT,

    + PERF_SAMPLE_BRANCH_TYPE_SAVE =
    + 1U << PERF_SAMPLE_BRANCH_TYPE_SAVE_SHIFT,
    +
    PERF_SAMPLE_BRANCH_MAX = 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT,
    };

    +/*
    + * Common flow change classification
    + */
    +enum {
    + PERF_BR_NONE = 0, /* unknown */
    + PERF_BR_JCC = 1, /* conditional jump */
    + PERF_BR_JMP = 2, /* jump */
    + PERF_BR_IND_JMP = 3, /* indirect jump */
    + PERF_BR_CALL = 4, /* call */
    + PERF_BR_IND_CALL = 5, /* indirect call */
    + PERF_BR_RET = 6, /* return */
    + PERF_BR_SYSCALL = 7, /* syscall */
    + PERF_BR_SYSRET = 8, /* syscall return */
    + PERF_BR_IRQ = 9, /* hw interrupt/trap/fault */
    + PERF_BR_INT = 10, /* sw interrupt */
    + PERF_BR_IRET = 11, /* return from interrupt */
    + PERF_BR_FAR_BRANCH = 12, /* not generic far branch type */
    + PERF_BR_MAX,
    +};
    +
    #define PERF_SAMPLE_BRANCH_PLM_ALL \
    (PERF_SAMPLE_BRANCH_USER|\
    PERF_SAMPLE_BRANCH_KERNEL|\
    @@ -999,6 +1024,7 @@ union perf_mem_data_src {
    * in_tx: running in a hardware transaction
    * abort: aborting a hardware transaction
    * cycles: cycles from last branch (or 0 if not supported)
    + * type: branch type
    */
    struct perf_branch_entry {
    __u64 from;
    @@ -1008,7 +1034,8 @@ struct perf_branch_entry {
    in_tx:1, /* in transaction */
    abort:1, /* transaction abort */
    cycles:16, /* cycle count to last branch */
    - reserved:44;
    + type:4, /* branch type */
    + reserved:40;
    };

    #endif /* _UAPI_LINUX_PERF_EVENT_H */
    diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
    index d09a9cd..69af012 100644
    --- a/tools/include/uapi/linux/perf_event.h
    +++ b/tools/include/uapi/linux/perf_event.h
    @@ -174,6 +174,8 @@ enum perf_branch_sample_type_shift {
    PERF_SAMPLE_BRANCH_NO_FLAGS_SHIFT = 14, /* no flags */
    PERF_SAMPLE_BRANCH_NO_CYCLES_SHIFT = 15, /* no cycles */

    + PERF_SAMPLE_BRANCH_TYPE_SAVE_SHIFT = 16, /* save branch type */
    +
    PERF_SAMPLE_BRANCH_MAX_SHIFT /* non-ABI */
    };

    @@ -198,9 +200,32 @@ enum perf_branch_sample_type {
    PERF_SAMPLE_BRANCH_NO_FLAGS = 1U << PERF_SAMPLE_BRANCH_NO_FLAGS_SHIFT,
    PERF_SAMPLE_BRANCH_NO_CYCLES = 1U << PERF_SAMPLE_BRANCH_NO_CYCLES_SHIFT,

    + PERF_SAMPLE_BRANCH_TYPE_SAVE =
    + 1U << PERF_SAMPLE_BRANCH_TYPE_SAVE_SHIFT,
    +
    PERF_SAMPLE_BRANCH_MAX = 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT,
    };

    +/*
    + * Common flow change classification
    + */
    +enum {
    + PERF_BR_NONE = 0, /* unknown */
    + PERF_BR_JCC = 1, /* conditional jump */
    + PERF_BR_JMP = 2, /* jump */
    + PERF_BR_IND_JMP = 3, /* indirect jump */
    + PERF_BR_CALL = 4, /* call */
    + PERF_BR_IND_CALL = 5, /* indirect call */
    + PERF_BR_RET = 6, /* return */
    + PERF_BR_SYSCALL = 7, /* syscall */
    + PERF_BR_SYSRET = 8, /* syscall return */
    + PERF_BR_IRQ = 9, /* hw interrupt/trap/fault */
    + PERF_BR_INT = 10, /* sw interrupt */
    + PERF_BR_IRET = 11, /* return from interrupt */
    + PERF_BR_FAR_BRANCH = 12, /* not generic far branch type */
    + PERF_BR_MAX,
    +};
    +
    #define PERF_SAMPLE_BRANCH_PLM_ALL \
    (PERF_SAMPLE_BRANCH_USER|\
    PERF_SAMPLE_BRANCH_KERNEL|\
    @@ -999,6 +1024,7 @@ union perf_mem_data_src {
    * in_tx: running in a hardware transaction
    * abort: aborting a hardware transaction
    * cycles: cycles from last branch (or 0 if not supported)
    + * type: branch type
    */
    struct perf_branch_entry {
    __u64 from;
    @@ -1008,7 +1034,8 @@ struct perf_branch_entry {
    in_tx:1, /* in transaction */
    abort:1, /* transaction abort */
    cycles:16, /* cycle count to last branch */
    - reserved:44;
    + type:4, /* branch type */
    + reserved:40;
    };

    #endif /* _UAPI_LINUX_PERF_EVENT_H */
    --
    2.7.4
    \
     
     \ /
      Last update: 2017-04-20 06:12    [W:4.738 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site