Commit cedd3614 authored Feb 24, 2022 by Anshuman Khandual Committed by Peter Zijlstra Mar 01, 2022

perf: Add irq and exception return branch types

This expands generic branch type classification by adding two more entries
there in i.e irq and exception return. Also updates the x86 implementation
to process X86_BR_IRET and X86_BR_IRQ 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.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1645681014-3346-1-git-send-email-anshuman.khandual@arm.com

parent 71a412ed

arch/x86/events/intel/lbr.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1329,10 +1329,10 @@ static int branch_map[X86_BR_TYPE_MAP_MAX] = {
		PERF_BR_SYSCALL, /* X86_BR_SYSCALL */
		PERF_BR_SYSRET, /* X86_BR_SYSRET */
		PERF_BR_UNKNOWN, /* X86_BR_INT */
		PERF_BR_UNKNOWN, /* X86_BR_IRET */
		PERF_BR_ERET, /* X86_BR_IRET */
		PERF_BR_COND, /* X86_BR_JCC */
		PERF_BR_UNCOND, /* X86_BR_JMP */
		PERF_BR_UNKNOWN, /* X86_BR_IRQ */
		PERF_BR_IRQ, /* X86_BR_IRQ */
		PERF_BR_IND_CALL, /* X86_BR_IND_CALL */
		PERF_BR_UNKNOWN, /* X86_BR_ABORT */
		PERF_BR_UNKNOWN, /* X86_BR_IN_TX */

include/uapi/linux/perf_event.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -251,6 +251,8 @@ enum {
		PERF_BR_SYSRET = 8, /* syscall return */
		PERF_BR_COND_CALL = 9, /* conditional function call */
		PERF_BR_COND_RET = 10, /* conditional function return */
		PERF_BR_ERET = 11, /* exception return */
		PERF_BR_IRQ = 12, /* irq */
		PERF_BR_MAX,
		};

tools/include/uapi/linux/perf_event.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -251,6 +251,8 @@ enum {
		PERF_BR_SYSRET = 8, /* syscall return */
		PERF_BR_COND_CALL = 9, /* conditional function call */
		PERF_BR_COND_RET = 10, /* conditional function return */
		PERF_BR_ERET = 11, /* exception return */
		PERF_BR_IRQ = 12, /* irq */
		PERF_BR_MAX,
		};

tools/perf/util/branch.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -49,7 +49,9 @@ const char *branch_type_name(int type)
		"SYSCALL",
		"SYSRET",
		"COND_CALL",
		"COND_RET"
		"COND_RET",
		"ERET",
		"IRQ"
		};

		if (type >= 0 && type < PERF_BR_MAX)