From 571d91dcadfa3cef499010b4eddb9b58b0da4d24 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Wed, 25 Oct 2023 13:16:19 -0700 Subject: perf: Add branch stack counters Currently, the additional information of a branch entry is stored in a u64 space. With more and more information added, the space is running out. For example, the information of occurrences of events will be added for each branch. Two places were suggested to append the counters. https://lore.kernel.org/lkml/20230802215814.GH231007@hirez.programming.kicks-ass.net/ One place is right after the flags of each branch entry. It changes the existing struct perf_branch_entry. The later ARCH specific implementation has to be really careful to consistently pick the right struct. The other place is right after the entire struct perf_branch_stack. The disadvantage is that the pointer of the extra space has to be recorded. The common interface perf_sample_save_brstack() has to be updated. The latter is much straightforward, and should be easily understood and maintained. It is implemented in the patch. Add a new branch sample type, PERF_SAMPLE_BRANCH_COUNTERS, to indicate the event which is recorded in the branch info. The "u64 counters" may store the occurrences of several events. The information regarding the number of events/counters and the width of each counter should be exposed via sysfs as a reference for the perf tool. Define the branch_counter_nr and branch_counter_width ABI here. The support will be implemented later in the Intel-specific patch. Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20231025201626.3000228-1-kan.liang@linux.intel.com --- kernel/events/core.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 3eb26c2c6e65..d27ffd80ed67 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7341,6 +7341,14 @@ void perf_output_sample(struct perf_output_handle *handle, if (branch_sample_hw_index(event)) perf_output_put(handle, data->br_stack->hw_idx); perf_output_copy(handle, data->br_stack->entries, size); + /* + * Add the extension space which is appended + * right after the struct perf_branch_stack. + */ + if (data->br_stack_cntr) { + size = data->br_stack->nr * sizeof(u64); + perf_output_copy(handle, data->br_stack_cntr, size); + } } else { /* * we always store at least the value of nr -- cgit From 652ffc2104ec1f69dd4a46313888c33527145ccf Mon Sep 17 00:00:00 2001 From: Greg KH Date: Mon, 12 Jun 2023 15:09:09 +0200 Subject: perf/core: Fix narrow startup race when creating the perf nr_addr_filters sysfs file Signed-off-by: Greg Kroah-Hartman Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/2023061204-decal-flyable-6090@gregkh --- kernel/events/core.c | 40 ++++++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 08250981d9f4..4f0c45ab8d7d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11408,9 +11408,32 @@ static DEVICE_ATTR_RW(perf_event_mux_interval_ms); static struct attribute *pmu_dev_attrs[] = { &dev_attr_type.attr, &dev_attr_perf_event_mux_interval_ms.attr, + &dev_attr_nr_addr_filters.attr, + NULL, +}; + +static umode_t pmu_dev_is_visible(struct kobject *kobj, struct attribute *a, int n) +{ + struct device *dev = kobj_to_dev(kobj); + struct pmu *pmu = dev_get_drvdata(dev); + + if (!pmu->nr_addr_filters) + return 0; + + return a->mode; + + return 0; +} + +static struct attribute_group pmu_dev_attr_group = { + .is_visible = pmu_dev_is_visible, + .attrs = pmu_dev_attrs, +}; + +static const struct attribute_group *pmu_dev_groups[] = { + &pmu_dev_attr_group, NULL, }; -ATTRIBUTE_GROUPS(pmu_dev); static int pmu_bus_running; static struct bus_type pmu_bus = { @@ -11447,18 +11470,11 @@ static int pmu_dev_alloc(struct pmu *pmu) if (ret) goto free_dev; - /* For PMUs with address filters, throw in an extra attribute: */ - if (pmu->nr_addr_filters) - ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); - - if (ret) - goto del_dev; - - if (pmu->attr_update) + if (pmu->attr_update) { ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update); - - if (ret) - goto del_dev; + if (ret) + goto del_dev; + } out: return ret; -- cgit From 388a1fb7da6aaa1970c7e2a7d7fcd983a87a8484 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 22 Nov 2023 11:07:56 +0100 Subject: perf: Fix the nr_addr_filters fix Thomas reported that commit 652ffc2104ec ("perf/core: Fix narrow startup race when creating the perf nr_addr_filters sysfs file") made the entire attribute group vanish, instead of only the nr_addr_filters attribute. Additionally a stray return. Insufficient coffee was involved with both writing and merging the patch. Fixes: 652ffc2104ec ("perf/core: Fix narrow startup race when creating the perf nr_addr_filters sysfs file") Reported-by: Thomas Richter Signed-off-by: Peter Zijlstra (Intel) Tested-by: Thomas Richter Link: https://lkml.kernel.org/r/20231122100756.GP8262@noisy.programming.kicks-ass.net --- kernel/events/core.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 4f0c45ab8d7d..59b332cce9e7 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11417,12 +11417,10 @@ static umode_t pmu_dev_is_visible(struct kobject *kobj, struct attribute *a, int struct device *dev = kobj_to_dev(kobj); struct pmu *pmu = dev_get_drvdata(dev); - if (!pmu->nr_addr_filters) + if (n == 2 && !pmu->nr_addr_filters) return 0; return a->mode; - - return 0; } static struct attribute_group pmu_dev_attr_group = { -- cgit