From 742015ff12ae27324b8ad2d28e43da6743529bad Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 9 Aug 2017 18:14:06 +0200 Subject: perf: Fix header.size for namespace events Reset header size for namespace events, otherwise it only gets bigger in ctx iterations. Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra (Intel) Fixes: e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info") Link: http://lkml.kernel.org/n/tip-nlo4gonz9d4guyb8153ukzt0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- kernel/events/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel/events/core.c') diff --git a/kernel/events/core.c b/kernel/events/core.c index 81dd57b9e5e3..aa21555972aa 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6640,6 +6640,7 @@ static void perf_event_namespaces_output(struct perf_event *event, struct perf_namespaces_event *namespaces_event = data; struct perf_output_handle handle; struct perf_sample_data sample; + u16 header_size = namespaces_event->event_id.header.size; int ret; if (!perf_event_namespaces_match(event)) @@ -6650,7 +6651,7 @@ static void perf_event_namespaces_output(struct perf_event *event, ret = perf_output_begin(&handle, event, namespaces_event->event_id.header.size); if (ret) - return; + goto out; namespaces_event->event_id.pid = perf_event_pid(event, namespaces_event->task); @@ -6662,6 +6663,8 @@ static void perf_event_namespaces_output(struct perf_event *event, perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); +out: + namespaces_event->event_id.header.size = header_size; } static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, -- cgit From 313ccb96159489eabdbdcf4deb34e7fbac17557d Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Sun, 7 Jan 2018 17:03:47 +0100 Subject: perf: Allocate context task_ctx_data for child event Currently we use perf_event_context::task_ctx_data to save and restore the LBR status when the task is scheduled out and in. We don't allocate it for child contexts, which results in shorter task's LBR stack, because we don't save the history from previous run and start over every time we schedule the task in. I made a test to generate samples with LBR call stack and got higher numbers on bigger chain depths: before: after: LBR call chain: nr: 1 60561 498127 LBR call chain: nr: 2 0 0 LBR call chain: nr: 3 107030 2172 LBR call chain: nr: 4 466685 62758 LBR call chain: nr: 5 2307319 878046 LBR call chain: nr: 6 48713 495218 LBR call chain: nr: 7 1040 4551 LBR call chain: nr: 8 481 172 LBR call chain: nr: 9 878 120 LBR call chain: nr: 10 2377 6698 LBR call chain: nr: 11 28830 151487 LBR call chain: nr: 12 29347 339867 LBR call chain: nr: 13 4 22 LBR call chain: nr: 14 3 53 Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Namhyung Kim Fixes: 4af57ef28c2c ("perf: Add pmu specific data for perf task context") Link: http://lkml.kernel.org/r/20180107160356.28203-4-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- kernel/events/core.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'kernel/events/core.c') diff --git a/kernel/events/core.c b/kernel/events/core.c index 4df5b695bf0d..55fb648a32b0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10703,6 +10703,19 @@ inherit_event(struct perf_event *parent_event, if (IS_ERR(child_event)) return child_event; + + if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) && + !child_ctx->task_ctx_data) { + struct pmu *pmu = child_event->pmu; + + child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size, + GFP_KERNEL); + if (!child_ctx->task_ctx_data) { + free_event(child_event); + return NULL; + } + } + /* * is_orphaned_event() and list_add_tail(&parent_event->child_list) * must be under the same lock in order to serialize against @@ -10713,6 +10726,7 @@ inherit_event(struct perf_event *parent_event, if (is_orphaned_event(parent_event) || !atomic_long_inc_not_zero(&parent_event->refcount)) { mutex_unlock(&parent_event->child_mutex); + /* task_ctx_data is freed with child_ctx */ free_event(child_event); return NULL; } -- cgit From 8cf7e0e22414f5acf85ecb7cd0d4482e6c9696ae Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Sun, 7 Jan 2018 17:03:49 +0100 Subject: perf: Make perf_callchain function static And move it to core.c, because there's no caller of this function other than the one in core.c Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20180107160356.28203-6-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- kernel/events/core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/events/core.c') diff --git a/kernel/events/core.c b/kernel/events/core.c index 55fb648a32b0..5fc1ded4b450 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5980,6 +5980,22 @@ static u64 perf_virt_to_phys(u64 virt) return phys_addr; } +static struct perf_callchain_entry * +perf_callchain(struct perf_event *event, struct pt_regs *regs) +{ + bool kernel = !event->attr.exclude_callchain_kernel; + bool user = !event->attr.exclude_callchain_user; + /* Disallow cross-task user callchains. */ + bool crosstask = event->ctx->task && event->ctx->task != current; + const u32 max_stack = event->attr.sample_max_stack; + + if (!kernel && !user) + return NULL; + + return get_perf_callchain(regs, 0, kernel, user, + max_stack, crosstask, true); +} + void perf_prepare_sample(struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event, -- cgit From 99e818cc88889a2fa2f483b91b372c47b94b7c98 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Sun, 7 Jan 2018 17:03:50 +0100 Subject: perf: Return empty callchain instead of NULL It simplifies the code a bit, because we dump the callchain Link: http://lkml.kernel.org/n/tip-uqp7qd6aif47g39glnbu95yl@git.kernel.org even if it's empty. With 'empty' callchain we can remove all the NULL-checking code paths. Original-patch-from: Peter Zijlstra Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Namhyung Kim Link: http://lkml.kernel.org/r/20180107160356.28203-7-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- kernel/events/core.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-) (limited to 'kernel/events/core.c') diff --git a/kernel/events/core.c b/kernel/events/core.c index 5fc1ded4b450..4e1a1bf8d867 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5815,19 +5815,11 @@ void perf_output_sample(struct perf_output_handle *handle, perf_output_read(handle, event); if (sample_type & PERF_SAMPLE_CALLCHAIN) { - if (data->callchain) { - int size = 1; - - if (data->callchain) - size += data->callchain->nr; - - size *= sizeof(u64); + int size = 1; - __output_copy(handle, data->callchain, size); - } else { - u64 nr = 0; - perf_output_put(handle, nr); - } + size += data->callchain->nr; + size *= sizeof(u64); + __output_copy(handle, data->callchain, size); } if (sample_type & PERF_SAMPLE_RAW) { @@ -5980,6 +5972,8 @@ static u64 perf_virt_to_phys(u64 virt) return phys_addr; } +static struct perf_callchain_entry __empty_callchain = { .nr = 0, }; + static struct perf_callchain_entry * perf_callchain(struct perf_event *event, struct pt_regs *regs) { @@ -5988,12 +5982,14 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) /* Disallow cross-task user callchains. */ bool crosstask = event->ctx->task && event->ctx->task != current; const u32 max_stack = event->attr.sample_max_stack; + struct perf_callchain_entry *callchain; if (!kernel && !user) - return NULL; + return &__empty_callchain; - return get_perf_callchain(regs, 0, kernel, user, - max_stack, crosstask, true); + callchain = get_perf_callchain(regs, 0, kernel, user, + max_stack, crosstask, true); + return callchain ?: &__empty_callchain; } void perf_prepare_sample(struct perf_event_header *header, @@ -6018,9 +6014,7 @@ void perf_prepare_sample(struct perf_event_header *header, int size = 1; data->callchain = perf_callchain(event, regs); - - if (data->callchain) - size += data->callchain->nr; + size += data->callchain->nr; header->size += size * sizeof(u64); } -- cgit