Add parser and parent shared_ptr to PerfEventArray

This commit is contained in:
Pragyansh Chaturvedi
2025-10-20 00:10:54 +05:30
parent cbfe6ae95e
commit 8babf3087b
3 changed files with 56 additions and 51 deletions

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@ -1,37 +0,0 @@
#ifndef PYLIBBPF_PERF_EVENT_ARRAY_H
#define PYLIBBPF_PERF_EVENT_ARRAY_H
#include <libbpf.h>
#include <pybind11/functional.h>
#include <pybind11/pybind11.h>
#include <string>
class StructParser;
namespace py = pybind11;
class PerfEventArray {
private:
struct perf_buffer *pb_;
py::function callback_;
py::function lost_callback_;
std::shared_ptr<StructParser> parser_;
std::string struct_name_;
// Static callback wrappers for C API
static void sample_callback_wrapper(void *ctx, int cpu, void *data,
unsigned int size);
static void lost_callback_wrapper(void *ctx, int cpu, unsigned long long cnt);
public:
PerfEventArray(int map_fd, int page_cnt, py::function callback,
py::object lost_callback = py::none());
~PerfEventArray();
int poll(int timeout_ms);
int consume();
[[nodiscard]] int fd() const;
};
#endif // PYLIBBPF_PERF_EVENT_ARRAY_H

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@ -1,11 +1,17 @@
#include "perf_event_array.h"
#include "core/bpf_exception.h"
#include "core/bpf_map.h"
PerfEventArray::PerfEventArray(int map_fd, int page_cnt, py::function callback,
py::object lost_callback)
: pb_(nullptr), callback_(std::move(callback)),
PerfEventArray::PerfEventArray(std::shared_ptr<BpfMap> map, int page_cnt,
py::function callback, py::object lost_callback)
: map_(map), pb_(nullptr), callback_(std::move(callback)),
lost_callback_(lost_callback) {
if (map->get_type() != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
throw BpfException("Map '" + map->get_name() +
"' is not a PERF_EVENT_ARRAY");
}
if (page_cnt <= 0 || (page_cnt & (page_cnt - 1)) != 0) {
throw BpfException("page_cnt must be a positive power of 2");
}
@ -14,7 +20,7 @@ PerfEventArray::PerfEventArray(int map_fd, int page_cnt, py::function callback,
pb_opts.sz = sizeof(pb_opts); // Required for forward compatibility
pb_ = perf_buffer__new(
map_fd, page_cnt,
map->get_fd(), page_cnt,
sample_callback_wrapper, // sample_cb
lost_callback.is_none() ? nullptr : lost_callback_wrapper, // lost_cb
this, // ctx
@ -27,6 +33,25 @@ PerfEventArray::PerfEventArray(int map_fd, int page_cnt, py::function callback,
}
}
PerfEventArray::PerfEventArray(std::shared_ptr<BpfMap> map, int page_cnt,
py::function callback,
const std::string &struct_name,
py::object lost_callback)
: PerfEventArray(map, page_cnt, callback, lost_callback) {
auto parent = map->get_parent();
if (!parent) {
throw BpfException("Parent BpfObject has been destroyed");
}
parser_ = parent->get_struct_parser();
struct_name_ = struct_name;
if (!parser_) {
throw BpfException("No struct definitions available");
}
}
PerfEventArray::~PerfEventArray() {
if (pb_) {
perf_buffer__free(pb_);
@ -34,7 +59,7 @@ PerfEventArray::~PerfEventArray() {
}
void PerfEventArray::sample_callback_wrapper(void *ctx, int cpu, void *data,
unsigned int size) {
unsigned int size) {
auto *self = static_cast<PerfEventArray *>(ctx);
// Acquire GIL for Python calls
@ -44,15 +69,23 @@ void PerfEventArray::sample_callback_wrapper(void *ctx, int cpu, void *data,
// Convert data to Python bytes
py::bytes py_data(static_cast<const char *>(data), size);
// Call Python callback: callback(cpu, data, size)
self->callback_(cpu, py_data, size);
if (self->parser_ && !self->struct_name_.empty()) {
py::object event = self->parser_->parse(self->struct_name_, py_data);
self->callback_(cpu, event);
} else {
self->callback_(cpu, py_data);
}
} catch (const py::error_already_set &e) {
PyErr_Print();
} catch (const std::exception &e) {
py::gil_scoped_acquire acquire;
py::print("C++ error in perf callback:", e.what());
}
}
void PerfEventArray::lost_callback_wrapper(void *ctx, int cpu,
unsigned long long cnt) {
unsigned long long cnt) {
auto *self = static_cast<PerfEventArray *>(ctx);
if (self->lost_callback_.is_none()) {

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@ -1,5 +1,5 @@
#ifndef PYLIBBPF_BPF_PERF_BUFFER_H
#define PYLIBBPF_BPF_PERF_BUFFER_H
#ifndef PYLIBBPF_PERF_EVENT_ARRAY_H
#define PYLIBBPF_PERF_EVENT_ARRAY_H
#include <libbpf.h>
#include <pybind11/functional.h>
@ -7,11 +7,13 @@
#include <string>
class StructParser;
class BpfMap;
namespace py = pybind11;
class PerfEventArray {
private:
std::shared_ptr<BpfMap> map_;
struct perf_buffer *pb_;
py::function callback_;
py::function lost_callback_;
@ -25,13 +27,20 @@ private:
static void lost_callback_wrapper(void *ctx, int cpu, unsigned long long cnt);
public:
PerfEventArray(int map_fd, int page_cnt, py::function callback,
py::object lost_callback = py::none());
PerfEventArray(std::shared_ptr<BpfMap> map, int page_cnt,
py::function callback, py::object lost_callback = py::none());
PerfEventArray(std::shared_ptr<BpfMap> map, int page_cnt,
py::function callback, const std::string &struct_name,
py::object lost_callback = py::none());
~PerfEventArray();
PerfEventArray(const PerfEventArray &) = delete;
PerfEventArray &operator=(const PerfEventArray &) = delete;
int poll(int timeout_ms);
int consume();
[[nodiscard]] int fd() const;
[[nodiscard]] std::shared_ptr<BpfMap> get_map() const { return map_; }
};
#endif // PYLIBBPF_BPF_PERF_BUFFER_H
#endif // PYLIBBPF_PERF_EVENT_ARRAY_H