x86, perf_counter, bts: Optimize BTS overflow handling
Draining the BTS buffer on a buffer overflow interrupt takes too long resulting in a kernel lockup when tracing the kernel. Restructure perf_counter sampling into sample creation and sample output. Prepare a single reference sample for BTS sampling and update the from and to address fields when draining the BTS buffer. Drain the entire BTS buffer between a single perf_output_begin() / perf_output_end() pair. Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090915130023.A16204@sedona.ch.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Markus Metzger
committed by
Ingo Molnar
Ingo Molnar
parent
4b77a72977
commit
5622f295b5
@@ -2512,18 +2512,6 @@ __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
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/*
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* Output
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*/
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struct perf_output_handle {
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struct perf_counter *counter;
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struct perf_mmap_data *data;
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unsigned long head;
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unsigned long offset;
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int nmi;
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int sample;
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int locked;
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unsigned long flags;
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};
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static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
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unsigned long offset, unsigned long head)
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{
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@@ -2633,8 +2621,8 @@ out:
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local_irq_restore(handle->flags);
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}
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static void perf_output_copy(struct perf_output_handle *handle,
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const void *buf, unsigned int len)
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void perf_output_copy(struct perf_output_handle *handle,
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const void *buf, unsigned int len)
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{
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unsigned int pages_mask;
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unsigned int offset;
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@@ -2669,12 +2657,9 @@ static void perf_output_copy(struct perf_output_handle *handle,
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WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
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}
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#define perf_output_put(handle, x) \
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perf_output_copy((handle), &(x), sizeof(x))
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static int perf_output_begin(struct perf_output_handle *handle,
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struct perf_counter *counter, unsigned int size,
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int nmi, int sample)
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int perf_output_begin(struct perf_output_handle *handle,
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struct perf_counter *counter, unsigned int size,
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int nmi, int sample)
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{
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struct perf_counter *output_counter;
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struct perf_mmap_data *data;
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@@ -2756,7 +2741,7 @@ out:
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return -ENOSPC;
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}
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static void perf_output_end(struct perf_output_handle *handle)
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void perf_output_end(struct perf_output_handle *handle)
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{
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struct perf_counter *counter = handle->counter;
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struct perf_mmap_data *data = handle->data;
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@@ -2870,82 +2855,151 @@ static void perf_output_read(struct perf_output_handle *handle,
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perf_output_read_one(handle, counter);
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}
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void perf_counter_output(struct perf_counter *counter, int nmi,
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struct perf_sample_data *data)
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void perf_output_sample(struct perf_output_handle *handle,
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struct perf_event_header *header,
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struct perf_sample_data *data,
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struct perf_counter *counter)
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{
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u64 sample_type = data->type;
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perf_output_put(handle, *header);
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if (sample_type & PERF_SAMPLE_IP)
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perf_output_put(handle, data->ip);
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if (sample_type & PERF_SAMPLE_TID)
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perf_output_put(handle, data->tid_entry);
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if (sample_type & PERF_SAMPLE_TIME)
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perf_output_put(handle, data->time);
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if (sample_type & PERF_SAMPLE_ADDR)
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perf_output_put(handle, data->addr);
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if (sample_type & PERF_SAMPLE_ID)
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perf_output_put(handle, data->id);
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if (sample_type & PERF_SAMPLE_STREAM_ID)
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perf_output_put(handle, data->stream_id);
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if (sample_type & PERF_SAMPLE_CPU)
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perf_output_put(handle, data->cpu_entry);
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if (sample_type & PERF_SAMPLE_PERIOD)
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perf_output_put(handle, data->period);
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if (sample_type & PERF_SAMPLE_READ)
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perf_output_read(handle, counter);
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if (sample_type & PERF_SAMPLE_CALLCHAIN) {
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if (data->callchain) {
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int size = 1;
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if (data->callchain)
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size += data->callchain->nr;
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size *= sizeof(u64);
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perf_output_copy(handle, data->callchain, size);
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} else {
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u64 nr = 0;
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perf_output_put(handle, nr);
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}
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}
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if (sample_type & PERF_SAMPLE_RAW) {
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if (data->raw) {
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perf_output_put(handle, data->raw->size);
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perf_output_copy(handle, data->raw->data,
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data->raw->size);
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} else {
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struct {
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u32 size;
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u32 data;
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} raw = {
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.size = sizeof(u32),
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.data = 0,
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};
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perf_output_put(handle, raw);
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}
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}
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}
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void perf_prepare_sample(struct perf_event_header *header,
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struct perf_sample_data *data,
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struct perf_counter *counter,
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struct pt_regs *regs)
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{
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int ret;
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u64 sample_type = counter->attr.sample_type;
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struct perf_output_handle handle;
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struct perf_event_header header;
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u64 ip;
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struct {
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u32 pid, tid;
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} tid_entry;
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struct perf_callchain_entry *callchain = NULL;
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int callchain_size = 0;
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u64 time;
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struct {
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u32 cpu, reserved;
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} cpu_entry;
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header.type = PERF_EVENT_SAMPLE;
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header.size = sizeof(header);
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data->type = sample_type;
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header.misc = 0;
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header.misc |= perf_misc_flags(data->regs);
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header->type = PERF_EVENT_SAMPLE;
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header->size = sizeof(*header);
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header->misc = 0;
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header->misc |= perf_misc_flags(regs);
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if (sample_type & PERF_SAMPLE_IP) {
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ip = perf_instruction_pointer(data->regs);
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header.size += sizeof(ip);
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data->ip = perf_instruction_pointer(regs);
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header->size += sizeof(data->ip);
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}
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if (sample_type & PERF_SAMPLE_TID) {
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/* namespace issues */
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tid_entry.pid = perf_counter_pid(counter, current);
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tid_entry.tid = perf_counter_tid(counter, current);
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data->tid_entry.pid = perf_counter_pid(counter, current);
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data->tid_entry.tid = perf_counter_tid(counter, current);
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header.size += sizeof(tid_entry);
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header->size += sizeof(data->tid_entry);
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}
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if (sample_type & PERF_SAMPLE_TIME) {
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/*
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* Maybe do better on x86 and provide cpu_clock_nmi()
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*/
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time = sched_clock();
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data->time = sched_clock();
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header.size += sizeof(u64);
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header->size += sizeof(data->time);
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}
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if (sample_type & PERF_SAMPLE_ADDR)
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header.size += sizeof(u64);
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header->size += sizeof(data->addr);
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if (sample_type & PERF_SAMPLE_ID)
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header.size += sizeof(u64);
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if (sample_type & PERF_SAMPLE_ID) {
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data->id = primary_counter_id(counter);
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if (sample_type & PERF_SAMPLE_STREAM_ID)
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header.size += sizeof(u64);
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header->size += sizeof(data->id);
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}
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if (sample_type & PERF_SAMPLE_STREAM_ID) {
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data->stream_id = counter->id;
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header->size += sizeof(data->stream_id);
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}
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if (sample_type & PERF_SAMPLE_CPU) {
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header.size += sizeof(cpu_entry);
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data->cpu_entry.cpu = raw_smp_processor_id();
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data->cpu_entry.reserved = 0;
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cpu_entry.cpu = raw_smp_processor_id();
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cpu_entry.reserved = 0;
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header->size += sizeof(data->cpu_entry);
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}
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if (sample_type & PERF_SAMPLE_PERIOD)
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header.size += sizeof(u64);
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header->size += sizeof(data->period);
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if (sample_type & PERF_SAMPLE_READ)
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header.size += perf_counter_read_size(counter);
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header->size += perf_counter_read_size(counter);
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if (sample_type & PERF_SAMPLE_CALLCHAIN) {
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callchain = perf_callchain(data->regs);
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int size = 1;
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if (callchain) {
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callchain_size = (1 + callchain->nr) * sizeof(u64);
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header.size += callchain_size;
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} else
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header.size += sizeof(u64);
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data->callchain = perf_callchain(regs);
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if (data->callchain)
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size += data->callchain->nr;
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header->size += size * sizeof(u64);
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}
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if (sample_type & PERF_SAMPLE_RAW) {
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@@ -2957,69 +3011,23 @@ void perf_counter_output(struct perf_counter *counter, int nmi,
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size += sizeof(u32);
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WARN_ON_ONCE(size & (sizeof(u64)-1));
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header.size += size;
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header->size += size;
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}
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}
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ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
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if (ret)
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static void perf_counter_output(struct perf_counter *counter, int nmi,
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struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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struct perf_output_handle handle;
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struct perf_event_header header;
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perf_prepare_sample(&header, data, counter, regs);
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if (perf_output_begin(&handle, counter, header.size, nmi, 1))
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return;
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perf_output_put(&handle, header);
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if (sample_type & PERF_SAMPLE_IP)
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perf_output_put(&handle, ip);
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if (sample_type & PERF_SAMPLE_TID)
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perf_output_put(&handle, tid_entry);
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if (sample_type & PERF_SAMPLE_TIME)
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perf_output_put(&handle, time);
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if (sample_type & PERF_SAMPLE_ADDR)
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perf_output_put(&handle, data->addr);
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if (sample_type & PERF_SAMPLE_ID) {
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u64 id = primary_counter_id(counter);
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perf_output_put(&handle, id);
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}
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if (sample_type & PERF_SAMPLE_STREAM_ID)
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perf_output_put(&handle, counter->id);
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if (sample_type & PERF_SAMPLE_CPU)
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perf_output_put(&handle, cpu_entry);
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if (sample_type & PERF_SAMPLE_PERIOD)
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perf_output_put(&handle, data->period);
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if (sample_type & PERF_SAMPLE_READ)
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perf_output_read(&handle, counter);
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if (sample_type & PERF_SAMPLE_CALLCHAIN) {
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if (callchain)
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perf_output_copy(&handle, callchain, callchain_size);
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else {
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u64 nr = 0;
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perf_output_put(&handle, nr);
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}
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}
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if (sample_type & PERF_SAMPLE_RAW) {
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if (data->raw) {
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perf_output_put(&handle, data->raw->size);
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perf_output_copy(&handle, data->raw->data, data->raw->size);
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} else {
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struct {
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u32 size;
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u32 data;
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} raw = {
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.size = sizeof(u32),
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.data = 0,
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};
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perf_output_put(&handle, raw);
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}
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}
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perf_output_sample(&handle, &header, data, counter);
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perf_output_end(&handle);
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}
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@@ -3501,7 +3509,8 @@ static void perf_log_throttle(struct perf_counter *counter, int enable)
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*/
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static int __perf_counter_overflow(struct perf_counter *counter, int nmi,
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int throttle, struct perf_sample_data *data)
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int throttle, struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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int events = atomic_read(&counter->event_limit);
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struct hw_perf_counter *hwc = &counter->hw;
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@@ -3557,14 +3566,15 @@ static int __perf_counter_overflow(struct perf_counter *counter, int nmi,
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perf_counter_disable(counter);
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}
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perf_counter_output(counter, nmi, data);
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perf_counter_output(counter, nmi, data, regs);
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return ret;
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}
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int perf_counter_overflow(struct perf_counter *counter, int nmi,
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struct perf_sample_data *data)
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struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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return __perf_counter_overflow(counter, nmi, 1, data);
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return __perf_counter_overflow(counter, nmi, 1, data, regs);
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}
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/*
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@@ -3602,7 +3612,8 @@ again:
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}
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static void perf_swcounter_overflow(struct perf_counter *counter,
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int nmi, struct perf_sample_data *data)
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int nmi, struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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struct hw_perf_counter *hwc = &counter->hw;
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int throttle = 0;
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@@ -3615,7 +3626,8 @@ static void perf_swcounter_overflow(struct perf_counter *counter,
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return;
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for (; overflow; overflow--) {
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if (__perf_counter_overflow(counter, nmi, throttle, data)) {
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if (__perf_counter_overflow(counter, nmi, throttle,
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data, regs)) {
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/*
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* We inhibit the overflow from happening when
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* hwc->interrupts == MAX_INTERRUPTS.
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@@ -3634,7 +3646,8 @@ static void perf_swcounter_unthrottle(struct perf_counter *counter)
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}
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static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
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int nmi, struct perf_sample_data *data)
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int nmi, struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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struct hw_perf_counter *hwc = &counter->hw;
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@@ -3643,11 +3656,11 @@ static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
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if (!hwc->sample_period)
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return;
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if (!data->regs)
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if (!regs)
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return;
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if (!atomic64_add_negative(nr, &hwc->period_left))
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perf_swcounter_overflow(counter, nmi, data);
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perf_swcounter_overflow(counter, nmi, data, regs);
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}
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static int perf_swcounter_is_counting(struct perf_counter *counter)
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@@ -3706,7 +3719,8 @@ static int perf_swcounter_match(struct perf_counter *counter,
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static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
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enum perf_type_id type,
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u32 event, u64 nr, int nmi,
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struct perf_sample_data *data)
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struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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struct perf_counter *counter;
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@@ -3715,8 +3729,8 @@ static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
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rcu_read_lock();
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list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
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if (perf_swcounter_match(counter, type, event, data->regs))
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perf_swcounter_add(counter, nr, nmi, data);
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if (perf_swcounter_match(counter, type, event, regs))
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perf_swcounter_add(counter, nr, nmi, data, regs);
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}
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rcu_read_unlock();
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}
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@@ -3737,7 +3751,8 @@ static int *perf_swcounter_recursion_context(struct perf_cpu_context *cpuctx)
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static void do_perf_swcounter_event(enum perf_type_id type, u32 event,
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u64 nr, int nmi,
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struct perf_sample_data *data)
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struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
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int *recursion = perf_swcounter_recursion_context(cpuctx);
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@@ -3750,7 +3765,7 @@ static void do_perf_swcounter_event(enum perf_type_id type, u32 event,
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barrier();
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perf_swcounter_ctx_event(&cpuctx->ctx, type, event,
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nr, nmi, data);
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nr, nmi, data, regs);
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rcu_read_lock();
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/*
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* doesn't really matter which of the child contexts the
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@@ -3758,7 +3773,7 @@ static void do_perf_swcounter_event(enum perf_type_id type, u32 event,
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*/
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ctx = rcu_dereference(current->perf_counter_ctxp);
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if (ctx)
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perf_swcounter_ctx_event(ctx, type, event, nr, nmi, data);
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perf_swcounter_ctx_event(ctx, type, event, nr, nmi, data, regs);
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rcu_read_unlock();
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barrier();
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@@ -3772,11 +3787,11 @@ void __perf_swcounter_event(u32 event, u64 nr, int nmi,
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struct pt_regs *regs, u64 addr)
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{
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struct perf_sample_data data = {
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.regs = regs,
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.addr = addr,
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};
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do_perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, &data);
|
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do_perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi,
|
||||
&data, regs);
|
||||
}
|
||||
|
||||
static void perf_swcounter_read(struct perf_counter *counter)
|
||||
@@ -3813,6 +3828,7 @@ static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
|
||||
{
|
||||
enum hrtimer_restart ret = HRTIMER_RESTART;
|
||||
struct perf_sample_data data;
|
||||
struct pt_regs *regs;
|
||||
struct perf_counter *counter;
|
||||
u64 period;
|
||||
|
||||
@@ -3820,17 +3836,17 @@ static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
|
||||
counter->pmu->read(counter);
|
||||
|
||||
data.addr = 0;
|
||||
data.regs = get_irq_regs();
|
||||
regs = get_irq_regs();
|
||||
/*
|
||||
* In case we exclude kernel IPs or are somehow not in interrupt
|
||||
* context, provide the next best thing, the user IP.
|
||||
*/
|
||||
if ((counter->attr.exclude_kernel || !data.regs) &&
|
||||
if ((counter->attr.exclude_kernel || !regs) &&
|
||||
!counter->attr.exclude_user)
|
||||
data.regs = task_pt_regs(current);
|
||||
regs = task_pt_regs(current);
|
||||
|
||||
if (data.regs) {
|
||||
if (perf_counter_overflow(counter, 0, &data))
|
||||
if (regs) {
|
||||
if (perf_counter_overflow(counter, 0, &data, regs))
|
||||
ret = HRTIMER_NORESTART;
|
||||
}
|
||||
|
||||
@@ -3966,15 +3982,17 @@ void perf_tpcounter_event(int event_id, u64 addr, u64 count, void *record,
|
||||
};
|
||||
|
||||
struct perf_sample_data data = {
|
||||
.regs = get_irq_regs(),
|
||||
.addr = addr,
|
||||
.raw = &raw,
|
||||
};
|
||||
|
||||
if (!data.regs)
|
||||
data.regs = task_pt_regs(current);
|
||||
struct pt_regs *regs = get_irq_regs();
|
||||
|
||||
do_perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, count, 1, &data);
|
||||
if (!regs)
|
||||
regs = task_pt_regs(current);
|
||||
|
||||
do_perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
|
||||
&data, regs);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(perf_tpcounter_event);
|
||||
|
||||
|
||||
Reference in New Issue
Block a user