BPFPerfBuffer: Make it more clear that timeout is milliseconds

src/cc/api/BPF.cc

@@ -443,11 +443,11 @@ StatusTuple BPF::close_perf_buffer(const std::string& name) {
   return StatusTuple(0);
 }
 
-void BPF::poll_perf_buffer(const std::string& name, int timeout) {
+void BPF::poll_perf_buffer(const std::string& name, int timeout_ms) {
   auto it = perf_buffers_.find(name);
   if (it == perf_buffers_.end())
     return;
-  it->second->poll(timeout);
+  it->second->poll(timeout_ms);
 }
 
 StatusTuple BPF::load_func(const std::string& func_name, bpf_prog_type type,

src/cc/api/BPF.h

@@ -141,7 +141,7 @@ class BPF {
                                void* cb_cookie = nullptr,
                                int page_cnt = DEFAULT_PERF_BUFFER_PAGE_CNT);
   StatusTuple close_perf_buffer(const std::string& name);
-  void poll_perf_buffer(const std::string& name, int timeout = -1);
+  void poll_perf_buffer(const std::string& name, int timeout_ms = -1);
 
   StatusTuple load_func(const std::string& func_name, enum bpf_prog_type type,
                         int& fd);

src/cc/api/BPFTable.cc

@@ -295,10 +295,10 @@ StatusTuple BPFPerfBuffer::close_all_cpu() {
   return StatusTuple(0);
 }
 
-void BPFPerfBuffer::poll(int timeout) {
+void BPFPerfBuffer::poll(int timeout_ms) {
   if (epfd_ < 0)
     return;
-  int cnt = epoll_wait(epfd_, ep_events_.get(), cpu_readers_.size(), timeout);
+  int cnt = epoll_wait(epfd_, ep_events_.get(), cpu_readers_.size(), timeout_ms);
   if (cnt <= 0)
     return;
   for (int i = 0; i < cnt; i++)

src/cc/api/BPFTable.h

@@ -309,7 +309,7 @@ class BPFPerfBuffer : public BPFTableBase<int, int> {
   StatusTuple open_all_cpu(perf_reader_raw_cb cb, perf_reader_lost_cb lost_cb,
                            void* cb_cookie, int page_cnt);
   StatusTuple close_all_cpu();
-  void poll(int timeout);
+  void poll(int timeout_ms);
 
  private:
   StatusTuple open_on_cpu(perf_reader_raw_cb cb, perf_reader_lost_cb lost_cb,