mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-10-03 23:58:05 +00:00
Code Issues Releases Wiki Activity

perf: Add system error and not in transaction branch types

Browse source 
This expands generic branch type classification by adding two more entries
there in i.e system error and not in transaction. This also updates the x86
implementation to process X86_BR_NO_TX records as appropriate. This changes
branch types reported to user space on x86 platform but it should not be a
problem. The possible scenarios and impacts are enumerated here.

 --------------------------------------------------------------------------
 | kernel | perf tool |                     Impact                        |
 --------------------------------------------------------------------------
 |   old  |    old    |  Works as before                                  |
 --------------------------------------------------------------------------
 |   old  |    new    |  PERF_BR_UNKNOWN is processed                     |
 --------------------------------------------------------------------------
 |   new  |    old    |  PERF_BR_NO_TX is blocked via old PERF_BR_MAX     |
 --------------------------------------------------------------------------
 |   new  |    new    |  PERF_BR_NO_TX is recognized                      |
 --------------------------------------------------------------------------

When PERF_BR_NO_TX is blocked via old PERF_BR_MAX (new kernel with old perf
tool) the user space might throw up an warning complaining about an
unrecognized branch types being reported, but it's expected. PERF_BR_SERROR
& PERF_BR_NO_TX branch types will be used for BRBE implementation on arm64
platform.

PERF_BR_NO_TX complements 'abort' and 'in_tx' elements in perf_branch_entry
which represent other transaction states for a given branch record. Because
this completes the transaction state classification.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: James Clark <james.clark@arm.com>
Link: https://lkml.kernel.org/r/20220824044822.70230-2-anshuman.khandual@arm.com
This commit is contained in:
Anshuman Khandual 2022-08-24 10:18:15 +05:30 committed by Peter Zijlstra
parent 0bc3be5b4b
commit a724ec8296
2 changed files with 3 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/events/utils.c
View file

@ -225,7 +225,7 @@ static int branch_map[X86_BR_TYPE_MAP_MAX] = {
PERF_BR_IND_CALL, /* X86_BR_IND_CALL */
PERF_BR_UNKNOWN, /* X86_BR_ABORT */
PERF_BR_UNKNOWN, /* X86_BR_IN_TX */
PERF_BR_UNKNOWN, /* X86_BR_NO_TX */
PERF_BR_NO_TX, /* X86_BR_NO_TX */
PERF_BR_CALL, /* X86_BR_ZERO_CALL */
PERF_BR_UNKNOWN, /* X86_BR_CALL_STACK */
PERF_BR_IND, /* X86_BR_IND_JMP */

2
include/uapi/linux/perf_event.h
View file

@ -253,6 +253,8 @@ enum {
PERF_BR_COND_RET = 10, /* conditional function return */
PERF_BR_ERET = 11, /* exception return */
PERF_BR_IRQ = 12, /* irq */
PERF_BR_SERROR = 13, /* system error */
PERF_BR_NO_TX = 14, /* not in transaction */
PERF_BR_MAX,
};