From 88bc63d00eb6defb661b9fd79957660b4dfa4b50 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 15 Oct 2024 23:23:54 -0700 Subject: [PATCH] perf tools: Do not set exclude_guest for precise_ip It seems perf sets the exclude_guest bit because of Intel PEBS implementation which uses a virtual address. IIUC now kernel disables PEBS when it goes to the guest mode regardless of this bit so we don't need to set it explicitly. At least for the other archs/vendors. I found the commit 1342798cc13e set the exclude_guest for precise_ip in the tool and the commit 20b279ddb38c added kernel side enforcement which was reverted by commit a706d965dcfd later. Actually it doesn't set the exclude_guest for the default event (cycles:P) already. $ grep -m1 vendor /proc/cpuinfo vendor_id : GenuineIntel $ perf record -e cycles:P true [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.002 MB perf.data (9 samples) ] $ perf evlist -v | tr ',' '\n' | grep -e exclude -e precise precise_ip: 3 But having lower 'p' modifier set the bit for some reason. $ perf record -e cycles:pp true [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.002 MB perf.data (9 samples) ] $ perf evlist -v | tr ',' '\n' | grep -e exclude -e precise precise_ip: 2 exclude_guest: 1 Actually AMD IBS suffers from this because it doesn't support excludes and having this bit effectively disables new features in the current implementation (due to the missing feature check). $ grep -m1 vendor /proc/cpuinfo vendor_id : AuthenticAMD $ perf record -W -e cycles:p -vv true 2>&1 | grep switching switching off PERF_FORMAT_LOST support switching off weight struct support switching off bpf_event switching off ksymbol switching off cloexec flag switching off mmap2 switching off exclude_guest, exclude_host By not setting exclude_guest, we can fix this inconsistency and the troubles. Reviewed-by: Ian Rogers Reviewed-by: James Clark Reviewed-by: Ravi Bangoria Acked-by: Kan Liang Cc: James Clark Cc: Atish Patra Cc: Mingwei Zhang Cc: Kajol Jain Cc: Thomas Richter Cc: Palmer Dabbelt Link: https://lore.kernel.org/r/20241016062359.264929-5-namhyung@kernel.org Signed-off-by: Namhyung Kim --- tools/perf/tests/parse-events.c | 12 ++++-------- tools/perf/util/parse-events.c | 4 ---- 2 files changed, 4 insertions(+), 12 deletions(-) diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c index 727683f249f6..82a19674a38f 100644 --- a/tools/perf/tests/parse-events.c +++ b/tools/perf/tests/parse-events.c @@ -898,8 +898,7 @@ static int test__group1(struct evlist *evlist) TEST_ASSERT_VAL("wrong exclude_user", !evsel->core.attr.exclude_user); TEST_ASSERT_VAL("wrong exclude_kernel", evsel->core.attr.exclude_kernel); TEST_ASSERT_VAL("wrong exclude_hv", evsel->core.attr.exclude_hv); - /* use of precise requires exclude_guest */ - TEST_ASSERT_VAL("wrong exclude guest", evsel->core.attr.exclude_guest); + TEST_ASSERT_VAL("wrong exclude guest", !evsel->core.attr.exclude_guest); TEST_ASSERT_VAL("wrong exclude host", !evsel->core.attr.exclude_host); TEST_ASSERT_VAL("wrong precise_ip", evsel->core.attr.precise_ip == 2); TEST_ASSERT_VAL("wrong leader", evsel__has_leader(evsel, leader)); @@ -1016,9 +1015,8 @@ static int test__group3(struct evlist *evlist __maybe_unused) TEST_ASSERT_VAL("wrong exclude_kernel", !evsel->core.attr.exclude_kernel); TEST_ASSERT_VAL("wrong exclude_hv", evsel->core.attr.exclude_hv); - /* use of precise requires exclude_guest */ TEST_ASSERT_VAL("wrong exclude guest", - evsel->core.attr.exclude_guest); + !evsel->core.attr.exclude_guest); TEST_ASSERT_VAL("wrong exclude host", !evsel->core.attr.exclude_host); TEST_ASSERT_VAL("wrong precise_ip", @@ -1103,8 +1101,7 @@ static int test__group4(struct evlist *evlist __maybe_unused) TEST_ASSERT_VAL("wrong exclude_user", !evsel->core.attr.exclude_user); TEST_ASSERT_VAL("wrong exclude_kernel", evsel->core.attr.exclude_kernel); TEST_ASSERT_VAL("wrong exclude_hv", evsel->core.attr.exclude_hv); - /* use of precise requires exclude_guest */ - TEST_ASSERT_VAL("wrong exclude guest", evsel->core.attr.exclude_guest); + TEST_ASSERT_VAL("wrong exclude guest", !evsel->core.attr.exclude_guest); TEST_ASSERT_VAL("wrong exclude host", !evsel->core.attr.exclude_host); TEST_ASSERT_VAL("wrong precise_ip", evsel->core.attr.precise_ip == 1); TEST_ASSERT_VAL("wrong group name", !evsel->group_name); @@ -1122,8 +1119,7 @@ static int test__group4(struct evlist *evlist __maybe_unused) TEST_ASSERT_VAL("wrong exclude_user", evsel->core.attr.exclude_user); TEST_ASSERT_VAL("wrong exclude_kernel", !evsel->core.attr.exclude_kernel); TEST_ASSERT_VAL("wrong exclude_hv", evsel->core.attr.exclude_hv); - /* use of precise requires exclude_guest */ - TEST_ASSERT_VAL("wrong exclude guest", evsel->core.attr.exclude_guest); + TEST_ASSERT_VAL("wrong exclude guest", !evsel->core.attr.exclude_guest); TEST_ASSERT_VAL("wrong exclude host", !evsel->core.attr.exclude_host); TEST_ASSERT_VAL("wrong precise_ip", evsel->core.attr.precise_ip == 2); TEST_ASSERT_VAL("wrong leader", evsel__has_leader(evsel, leader)); diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 687125570f56..afeb8d815bbf 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -1733,10 +1733,6 @@ static int parse_events__modifier_list(struct parse_events_state *parse_state, int exclude = eu | ek | eh; int exclude_GH = group ? evsel->exclude_GH : 0; - if (mod.precise) { - /* use of precise requires exclude_guest */ - eG = 1; - } if (mod.user) { if (!exclude) exclude = eu = ek = eh = 1; -- 2.50.1