WIP: Add pruning dead pid - draft static method

Author: IzabellaRaulin

examples/cpp/pyperf/PyPerfNativeStackTrace.cc

@@ -8,6 +8,7 @@
 #include <sys/uio.h>
 #include <errno.h>
 #include <unistd.h>
+#include <cxxabi.h>
 #include <cstdio>
 #include <cstring>
 #include <sstream>
@@ -31,13 +32,15 @@ time_t NativeStackTrace::now;
 UnwindCache NativeStackTrace::cache;
 
 
+
 NativeStackTrace::NativeStackTrace(uint32_t pid, const unsigned char *raw_stack,
                                    size_t stack_len, uintptr_t ip, uintptr_t sp) : error_occurred(false) {
   NativeStackTrace::stack = raw_stack;
   NativeStackTrace::stack_len = stack_len;
   NativeStackTrace::ip = ip;
   NativeStackTrace::sp = sp;
   NativeStackTrace::now = time(NULL);
+  logInfo(2,"DEBUGIZA: Welcome in NativeStackTrace, pid=%d\n", pid);
 
   if (stack_len == 0) {
     return;
@@ -56,11 +59,11 @@ NativeStackTrace::NativeStackTrace(uint32_t pid, const unsigned char *raw_stack,
   int res;
 
   // Pseudo-proactive way of implementing TTL - whenever any call is made, all expired entries are removed
-  cache_eviction(cache);
+  cache_eviction();
 
   // Check whether the entry for the process ID is presented in the cache
-  if (!is_cached(cache, pid)) {
-    logInfo(3,"The given key %d is not presented in the cache\n", pid);
+  if (!is_cached(pid)) {
+    logInfo(2,"The given key %d is not presented in the cache\n", pid);
 
     as = unw_create_addr_space(&my_accessors, 0);
     upt = _UPT_create(pid);
@@ -82,12 +85,12 @@ NativeStackTrace::NativeStackTrace(uint32_t pid, const unsigned char *raw_stack,
     }
 
     // Put to the cache
-    cache_put(cache, pid, cursor, as, upt);
+    cache_put(pid, cursor, as, upt);
 
   } else {
-    logInfo(3,"Found entry for the given key %d in the cache\n", pid);
+    logInfo(2,"Found entry for the given key %d in the cache\n", pid);
     // Get from the cache
-    UnwindCacheEntry cached_entry = cache_get(cache, pid);
+    UnwindCacheEntry cached_entry = cache_get(pid);
     cursor = cached_entry.cursor;
     as = cached_entry.as;
     upt = cached_entry.upt;
@@ -137,6 +140,11 @@ NativeStackTrace::NativeStackTrace(uint32_t pid, const unsigned char *raw_stack,
 
 }
 
+void NativeStackTrace::Prune_dead_pid(uint32_t dead_pid) {
+  logInfo(2, "DEBUGIZA: D. Try to call cache_delete %d\n", dead_pid);
+  cache_delete_key(dead_pid);
+}
+
 void NativeStackTrace::cleanup(void *upt, unw_addr_space_t as) {
   if (upt) {
     _UPT_destroy(upt);
@@ -230,75 +238,75 @@ bool NativeStackTrace::error_occured() const {
   return error_occurred;
 }
 
-bool NativeStackTrace::is_cached(const UnwindCache &map, const uint32_t &key) {
+bool NativeStackTrace::is_cached(const uint32_t &key) {
   try {
-      map.at(key);
+      cache.at(key);
       return true;
   }
   catch (const std::out_of_range&) {
-      logInfo(3, "No entry for %d in the cache\n", key);
+      logInfo(2, "No entry for %d in the cache\n", key);
   }
   return false;
 }
 
-UnwindCacheEntry NativeStackTrace::cache_get(const UnwindCache &map, const uint32_t &key) {
-  const UnwindCacheEntry & entry = map.at(key);
+UnwindCacheEntry NativeStackTrace::cache_get(const uint32_t &key) {
+  const UnwindCacheEntry & entry = cache.at(key);
   return entry;
 }
 
 // cache_put adds a new entry to the unwind cache if the capacity allows
-void NativeStackTrace::cache_put(UnwindCache &mp, const uint32_t &key, const unw_cursor_t cursor, const unw_addr_space_t as, void *upt) {  
+void NativeStackTrace::cache_put(const uint32_t &key, const unw_cursor_t cursor, const unw_addr_space_t as, void *upt) {  
   // Check available capacity
   if (cache_size() > NativeStackTrace::CacheMaxSizeMB*1024*1024 - cache_single_entry_size()) { 
-    logInfo(3, "The cache usage is %.2f MB, close to reaching the max memory usage (%d MB)\n", cache_size_KB()/1024, NativeStackTrace::CacheMaxSizeMB);
-    logInfo(3, "Skipping adding an entry for %d to the cache\n", key);     
+    logInfo(2, "The cache usage is %.2f MB, close to reaching the max memory usage (%d MB)\n", cache_size_KB()/1024, NativeStackTrace::CacheMaxSizeMB);
+    logInfo(2, "Skipping adding an entry for %d to the cache\n", key);     
     return;
   }
 
   UnwindCacheEntry entry = {cursor, as, upt, now};
-  mp[key] = entry;
-  logInfo(3, "New entry for %d was added to the cache\n", key);
+  cache[key] = entry;
+  logInfo(2, "New entry for %d was added to the cache\n", key);
 }
 
 // cache_delete_key removes the element from the cache and destroys unwind address space and UPT
 // to ensure that all memory and other resources are freed up
-bool NativeStackTrace::cache_delete_key(UnwindCache &mp, const uint32_t &key) {
+bool NativeStackTrace::cache_delete_key(const uint32_t &key) {
   UnwindCacheEntry e;
   try {
-    e = cache_get(mp, key);
+    e = cache_get(key);
   }
   catch (const std::out_of_range&) {
-    logInfo(3, "Failed to delete entry for %d: no such key in the cache\n", key);
+    logInfo(2, "Failed to delete entry for %d: no such key in the cache\n", key);
     return false;
   }
 
-  mp.erase(key);
+  cache.erase(key);
   cleanup(e.upt, e.as);
-  logInfo(3, "The entry for %d was deleted from the cache\n", key);
+  logInfo(2, "The entry for %d was deleted from the cache\n", key);
   return true;
 }
 
 // cache_single_entry_size returns the number of bytes taken by single entry
-uint32_t NativeStackTrace::cache_single_entry_size() const {  
+uint32_t NativeStackTrace::cache_single_entry_size() {  
   return sizeof(decltype(cache)::key_type) + sizeof(decltype(cache)::mapped_type);
 }
 
 // cache_size returns the number of bytes currently in use by the cache
-uint32_t NativeStackTrace::cache_size() const {  
+uint32_t NativeStackTrace::cache_size() {  
   return sizeof(cache) + cache.size()*cache_single_entry_size();
 }
 
 // cache_size_KB returns the number of kilobytes currently in use by the cache
-float NativeStackTrace::cache_size_KB() const {  
+float NativeStackTrace::cache_size_KB() {  
   return cache_size()/1024;
 }
 
 // cache_eviction removes elements older than 5 minutes (CacheMaxTTL=300)
-void NativeStackTrace::cache_eviction(UnwindCache &mp) {
+void NativeStackTrace::cache_eviction() {
   std::vector<uint32_t> keys_to_delete;
   float _prev_cache_size = cache_size_KB();
 
-  for(std::map<uint32_t, UnwindCacheEntry>::iterator iter = mp.begin(); iter != mp.end(); ++iter)
+  for(std::map<uint32_t, UnwindCacheEntry>::iterator iter = cache.begin(); iter != cache.end(); ++iter)
   {
     uint32_t k =  iter->first;
     const UnwindCacheEntry & e =  iter->second;
@@ -310,13 +318,13 @@ void NativeStackTrace::cache_eviction(UnwindCache &mp) {
 
   // Delete expired entries
   for( size_t i = 0; i < keys_to_delete.size(); i++ ) {
-      cache_delete_key(mp, keys_to_delete[i]);
+      cache_delete_key(keys_to_delete[i]);
   }
 
   if (keys_to_delete.size() > 0) {
     float _cache_size = cache_size_KB();
-    logInfo(3,"Evicted %d item(s) from the cache\n", keys_to_delete.size());
-    logInfo(3,"The cache usage after eviction action is %.2f KB (released %.2f KB)\n", _cache_size, _prev_cache_size - _cache_size);    
+    logInfo(2,"Evicted %d item(s) from the cache\n", keys_to_delete.size());
+    logInfo(2,"The cache usage after eviction action is %.2f KB (released %.2f KB)\n", _cache_size, _prev_cache_size - _cache_size);    
   }
 }
 

examples/cpp/pyperf/PyPerfNativeStackTrace.h

@@ -22,44 +22,46 @@ typedef struct {
 
 typedef std::map<uint32_t, UnwindCacheEntry> UnwindCache;
 
+
 class NativeStackTrace {
  public:
   explicit NativeStackTrace(uint32_t pid, const uint8_t *raw_stack,
                             size_t stack_len, uintptr_t ip, uintptr_t sp);
 
+  static void Prune_dead_pid(uint32_t dead_pid);
   std::vector<std::string> get_stack_symbol() const;
   bool error_occured() const;
  private:
   std::vector<std::string> symbols;
   bool error_occurred;
+  static UnwindCache cache;
 
   static const uint8_t *stack;
   static size_t stack_len;
   static uintptr_t ip;
   static uintptr_t sp;
   static time_t now;
 
-  static UnwindCache cache;
   static const uint16_t CacheMaxSizeMB;
   static const uint16_t CacheMaxTTL;
 
-  uint32_t cache_size() const; 
-  uint32_t cache_single_entry_size() const;
-  float cache_size_KB() const; 
+  static uint32_t cache_size(); 
+  static uint32_t cache_single_entry_size();
+  static float cache_size_KB(); 
 
   static int access_reg(unw_addr_space_t as, unw_regnum_t regnum,
                         unw_word_t *valp, int write, void *arg);
 
   static int access_mem(unw_addr_space_t as, unw_word_t addr, unw_word_t *valp,
                         int write, void *arg);
 
-  void cleanup(void *upt, unw_addr_space_t as);
+  static void cleanup(void *upt, unw_addr_space_t as);
 
-  bool is_cached(const UnwindCache &map, const uint32_t &key);
-  void cache_put(UnwindCache &map, const uint32_t &key, const unw_cursor_t cursor, const unw_addr_space_t as, void *upt);
-  UnwindCacheEntry cache_get(const UnwindCache &map, const uint32_t &key);
-  bool cache_delete_key(UnwindCache &map, const uint32_t &key);
-  void cache_eviction(UnwindCache &map);
+  bool is_cached(const uint32_t &key);
+  void cache_put(const uint32_t &key, const unw_cursor_t cursor, const unw_addr_space_t as, void *upt);
+  static UnwindCacheEntry cache_get(const uint32_t &key);
+  static bool cache_delete_key(const uint32_t &key);
+  static void cache_eviction();
 };
 
 }  // namespace pyperf

examples/cpp/pyperf/PyPerfProfiler.cc

@@ -29,6 +29,7 @@
 #include "PyPerfLoggingHelper.h"
 #include "PyPerfVersion.h"
 #include "PyPerfProc.h"
+#include "PyPerfNativeStackTrace.h"
 #include "bcc_elf.h"
 #include "bcc_proc.h"
 #include "bcc_syms.h"
@@ -235,20 +236,38 @@ bool PyPerfProfiler::populatePidTable() {
   auto pid_config_map = bpf_.get_hash_table<int, PidData>(kPidCfgTableName);
 
   logInfo(3, "Pruning dead pids\n");
+  logInfo(2, "DEBUGIZA: Pruning dead pids\n");
   auto pid_config_keys = pid_config_map.get_keys_offline();
   for (const auto pid : pid_config_keys) {
+    logInfo(2, "DEBUGIZA: Pruning dead pid=%d\n", pid);
     auto pos = std::find(pids.begin(), pids.end(), pid);
     if (pos == pids.end()) {
+      // no element found
+      logInfo(2, "DEBUGIZA: A. Pruning dead\n");
+      logInfo(2, "DEBUGIZA: A1. sizeof(pid_config_map)=%d\n", pid_config_keys.size());
+      logInfo(2, "DEBUGIZA: A1. sizeof(pids)=%d\n", pids.size());
       pid_config_map.remove_value(pid);
+      NativeStackTrace::Prune_dead_pid(pid);
+      // logInfo(2, "DEBUGIZA: A2. sizeof(pid_config_map)=%d\n", pid_config_map.size());
+      logInfo(2, "DEBUGIZA: A2. sizeof(pids)=%d\n", pids.size());
     }
     else {
+      logInfo(2, "DEBUGIZA: B Pruning dead wszedl\n");
       result = true;
+      // logInfo(2, "DEBUGIZA: B1. sizeof(pid_config_map)=%d\n", pid_config_map.size);
+      logInfo(2, "DEBUGIZA: B1. sizeof(pids)=%d\n", pids.size());
+    
+      // erase to avoid re-population (see below)
       pids.erase(pos);
+      // logInfo(2, "DEBUGIZA: B2. sizeof(pid_config_map)=%d\n", pid_config_map.size());
+      logInfo(2, "DEBUGIZA: B2. sizeof(pids)=%d\n", pids.size());
+
     }
   }
 
   logInfo(3, "Populating pid table\n");
   for (const auto pid : pids) {
+    // update only those pids that have not been observed before
     PidData pidData;
 
     if (!tryTargetPid(pid, pidData)) {