mpl/ze: Add debug logging for specialized ipc handle cache

ZE uses a specialized cache contained within MPL by default. Because of
this, it will bypass the generic cache in the ch4 layer and not output
any cache debug messages. Add debug messages directly in MPL to mirror
the generic cache for now. Eventually we will remove the specialized
cache once the generic one reaches feature parity.

Author: raffenet

src/mpl/src/gpu/mpl_gpu_ze.c

@@ -28,6 +28,11 @@ MPL_SUPPRESS_OSX_HAS_NO_SYMBOLS_WARNING;
 #include "uthash.h"
 #include "utlist.h"
 
+/* support logging for cache hits and misses */
+#if defined (MPL_USE_DBG_LOGGING)
+extern MPL_dbg_class MPIDI_CH4_DBG_IPC;
+#endif /* MPL_USE_DBG_LOGGING */
+
 /* Latest Level-zero Specification:
  * http://spec.oneapi.com/level-zero/latest/index.html
  */
@@ -1694,6 +1699,8 @@ static int remove_stale_sender_cache(const void *ptr, uint64_t mem_id, int local
             HASH_FIND(hh, ipc_cache_tracked[memid_entry->dev_id], &mem_id, sizeof(uint64_t),
                       cache_entry);
             if (cache_entry) {
+                MPL_DBG_MSG_P(MPIDI_CH4_DBG_IPC, VERBOSE, "removing STALE gpu ipc handle for %p",
+                              ptr);
                 /* call putIpcHandle only if this ptr is still valid */
                 if (memid_entry->mem_id == mem_id && memid_entry->dev_id == local_dev_id) {
                     free_ipc_handle_cache(cache_entry);
@@ -1752,14 +1759,17 @@ int MPL_gpu_ipc_handle_create(const void *ptr, MPL_gpu_device_attr * ptr_attr,
     }
 
     if (cache_entry && cache_entry->handle_cached) {
+        MPL_DBG_MSG_P(MPIDI_CH4_DBG_IPC, VERBOSE, "cached gpu ipc handle HIT for %p", pbase);
         memcpy(ipc_handle, &cache_entry->ipc_handle, sizeof(MPL_gpu_ipc_mem_handle_t));
     } else {
+        MPL_DBG_MSG_P(MPIDI_CH4_DBG_IPC, VERBOSE, "cached gpu ipc handle MISS for %p", pbase);
         mpl_err = MPL_ze_ipc_handle_create(pbase, ptr_attr, local_dev_id, true, ipc_handle);
         if (mpl_err != MPL_SUCCESS) {
             goto fn_fail;
         }
 
         if (likely(MPL_gpu_info.specialized_cache)) {
+            MPL_DBG_MSG_P(MPIDI_CH4_DBG_IPC, VERBOSE, "caching NEW gpu ipc handle for %p", pbase);
             if (cache_entry) {
                 /* In the case where there was an entry, but no ipc handle yet */
                 cache_entry->handle_cached = true;