linux-kernel - [PATCH] perf/amd/ibs: Make IBS a core pmu

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Date:   Tue, 15 Nov 2022 15:09:04 +0530
From:   Ravi Bangoria <ravi.bangoria@....com>
To:     <peterz@...radead.org>
CC:     <ravi.bangoria@....com>, <acme@...nel.org>, <mark.rutland@....com>,
        <jolsa@...hat.com>, <namhyung@...nel.org>, <eranian@...gle.com>,
        <kan.liang@...ux.intel.com>, <bp@...en8.de>, <x86@...nel.org>,
        <linux-perf-users@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <sandipan.das@....com>, <ananth.narayan@....com>,
        <santosh.shukla@....com>
Subject: [PATCH] perf/amd/ibs: Make IBS a core pmu

So far, only one pmu was allowed to be registered as core pmu and thus
IBS pmus were being registered as uncore. However, with the event context
rewrite, that limitation no longer exists and thus IBS pmus can also be
registered as core pmu. This makes IBS much more usable, for ex, user
will be able to do per-process precise monitoring on AMD:

Before patch:
  $ sudo perf record -e cycles:pp ls
  Error:
  Invalid event (cycles:pp) in per-thread mode, enable system wide with '-a'

After patch:
  $ sudo perf record -e cycles:pp ls
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.017 MB perf.data (33 samples) ]

Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
---
Note:
This patch is dependent on the event context rewrite patch which is
already present in a tip tree:
  https://git.kernel.org/tip/tip/c/bd27568117664

 arch/x86/events/amd/ibs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index 3271735f0070..fbc2ce86f4b8 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -631,7 +631,7 @@ static const struct attribute_group *op_attr_update[] = {
 
 static struct perf_ibs perf_ibs_fetch = {
 	.pmu = {
-		.task_ctx_nr	= perf_invalid_context,
+		.task_ctx_nr	= perf_hw_context,
 
 		.event_init	= perf_ibs_init,
 		.add		= perf_ibs_add,
@@ -655,7 +655,7 @@ static struct perf_ibs perf_ibs_fetch = {
 
 static struct perf_ibs perf_ibs_op = {
 	.pmu = {
-		.task_ctx_nr	= perf_invalid_context,
+		.task_ctx_nr	= perf_hw_context,
 
 		.event_init	= perf_ibs_init,
 		.add		= perf_ibs_add,
-- 
2.37.3