perfmon: make less arch dependent

In preparation for enabling perfmon on Arm platforms, move some Intel
/arch specific logic into the /intel directory and update the CMake to
split the common code from arch specific files.

Since the dispatch_wrapper code is very different on Arm/Intel,
each arch can provide their own implementation + conduct any additional
arch specific config e.g. on Intel, all indexes from the mmap pages are
cached. The new method intel_config_dispatch_wrapper conducts this
config and returns a pointer to the dispatch wrapper to use.

Similarly, is_bundle_supported() looks very different on Arm/Intel, so
each implementation is to provide their own arch specific checks.

Two new callbacks/function ptrs are added in PERFMON_REGISTER_SOURCE to
support this - .bundle_support and .config_dispatch_wrapper.

Type: refactor
Signed-off-by: Zachary Leaf <zachary.leaf@arm.com>
Change-Id: Idd121ddcfd1cc80a57c949cecd64eb2db0ac8be3

8 files changed, 161 insertions, 101 deletions

diff --git a/src/plugins/perfmon/CMakeLists.txt b/src/plugins/perfmon/CMakeLists.txt
index c7b2a384cc2..59eddf01145 100644
--- a/src/plugins/perfmon/CMakeLists.txt
+++ b/src/plugins/perfmon/CMakeLists.txt
@@ -15,12 +15,8 @@ if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "amd64.*|x86_64.*|AMD64.*")
   return()
 endif()
 
-add_vpp_plugin(perfmon
-  SOURCES
-  cli.c
-  dispatch_wrapper.c
-  linux.c
-  perfmon.c
+list(APPEND ARCH_PMU_SOURCES
+  intel/dispatch_wrapper.c
   intel/core.c
   intel/uncore.c
   intel/bundle/backend_bound_core.c
@@ -38,6 +34,14 @@ add_vpp_plugin(perfmon
   intel/bundle/topdown_icelake.c
   intel/bundle/topdown_metrics.c
   intel/bundle/topdown_tremont.c
+)
+
+add_vpp_plugin(perfmon
+  SOURCES
+  cli.c
+  linux.c
+  perfmon.c
+  ${ARCH_PMU_SOURCES}
 
   COMPONENT
   vpp-plugin-devtools
diff --git a/src/plugins/perfmon/intel/core.c b/src/plugins/perfmon/intel/core.c
index 08a27b6a73f..5c4c336e2e8 100644
--- a/src/plugins/perfmon/intel/core.c
+++ b/src/plugins/perfmon/intel/core.c
@@ -16,6 +16,7 @@
 #include <vnet/vnet.h>
 #include <perfmon/perfmon.h>
 #include <perfmon/intel/core.h>
+#include <perfmon/intel/dispatch_wrapper.h>
 #include <linux/perf_event.h>
 
 static perfmon_event_t events[] = {
@@ -95,6 +96,53 @@ intel_core_get_event_type (u32 event)
     return PERFMON_EVENT_TYPE_GENERAL;
 }
 
+static u8
+is_enough_counters (perfmon_bundle_t *b)
+{
+  u8 bl[PERFMON_EVENT_TYPE_MAX];
+  u8 cpu[PERFMON_EVENT_TYPE_MAX];
+
+  clib_memset (&bl, 0, sizeof (bl));
+  clib_memset (&cpu, 0, sizeof (cpu));
+
+  /* how many does this uarch support */
+  if (!clib_get_pmu_counter_count (&cpu[PERFMON_EVENT_TYPE_FIXED],
+				   &cpu[PERFMON_EVENT_TYPE_GENERAL]))
+    return 0;
+
+  /* how many does the bundle require */
+  for (u16 i = 0; i < b->n_events; i++)
+    {
+      /* if source allows us to identify events, otherwise assume general */
+      if (b->src->get_event_type)
+	bl[b->src->get_event_type (b->events[i])]++;
+      else
+	bl[PERFMON_EVENT_TYPE_GENERAL]++;
+    }
+
+  /* consciously ignoring pseudo events here */
+  return cpu[PERFMON_EVENT_TYPE_GENERAL] >= bl[PERFMON_EVENT_TYPE_GENERAL] &&
+	 cpu[PERFMON_EVENT_TYPE_FIXED] >= bl[PERFMON_EVENT_TYPE_FIXED];
+}
+
+u8
+intel_bundle_supported (perfmon_bundle_t *b)
+{
+  perfmon_cpu_supports_t *supports = b->cpu_supports;
+
+  if (!is_enough_counters (b))
+    return 0;
+
+  if (!b->cpu_supports)
+    return 1;
+
+  for (int i = 0; i < b->n_cpu_supports; ++i)
+    if (supports[i].cpu_supports ())
+      return 1;
+
+  return 0;
+}
+
 PERFMON_REGISTER_SOURCE (intel_core) = {
   .name = "intel-core",
   .description = "intel arch core events",
@@ -103,4 +151,6 @@ PERFMON_REGISTER_SOURCE (intel_core) = {
   .init_fn = intel_core_init,
   .get_event_type = intel_core_get_event_type,
   .format_config = format_intel_core_config,
+  .bundle_support = intel_bundle_supported,
+  .config_dispatch_wrapper = intel_config_dispatch_wrapper,
 };
diff --git a/src/plugins/perfmon/intel/core.h b/src/plugins/perfmon/intel/core.h
index 98ab9e539dd..b2b0434acb3 100644
--- a/src/plugins/perfmon/intel/core.h
+++ b/src/plugins/perfmon/intel/core.h
@@ -16,6 +16,8 @@
 #ifndef __perfmon_intel_h
 #define __perfmon_intel_h
 
+u8 intel_bundle_supported (perfmon_bundle_t *b);
+
 #define PERF_INTEL_CODE(event, umask, edge, any, inv, cmask)                  \
   ((event) | (umask) << 8 | (edge) << 18 | (any) << 21 | (inv) << 23 |        \
    (cmask) << 24)
diff --git a/src/plugins/perfmon/dispatch_wrapper.c b/src/plugins/perfmon/intel/dispatch_wrapper.c
index 3ae1219fe04..d424b54b85f 100644
--- a/src/plugins/perfmon/dispatch_wrapper.c
+++ b/src/plugins/perfmon/intel/dispatch_wrapper.c
@@ -25,6 +25,8 @@
 
 #include <perfmon/perfmon.h>
 
+vlib_node_function_t *perfmon_dispatch_wrappers[PERF_MAX_EVENTS + 1];
+
 static_always_inline void
 perfmon_read_pmcs (u64 *counters, u32 *indexes, u8 n_counters)
 {
@@ -76,6 +78,68 @@ perfmon_dispatch_wrapper_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
   return rv;
 }
 
+static_always_inline u32
+perfmon_mmap_read_index (const struct perf_event_mmap_page *mmap_page)
+{
+  u32 idx;
+  u32 seq;
+
+  /* See documentation in /usr/include/linux/perf_event.h, for more details
+   * but the 2 main important things are:
+   *  1) if seq != mmap_page->lock, it means the kernel is currently updating
+   *     the user page and we need to read it again
+   *  2) if idx == 0, it means the perf event is currently turned off and we
+   *     just need to read the kernel-updated 'offset', otherwise we must also
+   *     add the current hw value (hence rdmpc) */
+  do
+    {
+      seq = mmap_page->lock;
+      CLIB_COMPILER_BARRIER ();
+
+      idx = mmap_page->index;
+
+      CLIB_COMPILER_BARRIER ();
+    }
+  while (mmap_page->lock != seq);
+
+  return idx;
+}
+
+static_always_inline clib_error_t *
+read_mmap_indexes (perfmon_bundle_t *b)
+{
+  perfmon_main_t *pm = &perfmon_main;
+  for (int i = 0; i < vec_len (pm->thread_runtimes); i++)
+    {
+      perfmon_thread_runtime_t *tr;
+      tr = vec_elt_at_index (pm->thread_runtimes, i);
+
+      for (int j = 0; j < b->n_events; j++)
+	{
+	  tr->indexes[j] = perfmon_mmap_read_index (tr->mmap_pages[j]);
+
+	  /* if a zero index is returned generate error */
+	  if (!tr->indexes[j])
+	    {
+	      return clib_error_return (0, "invalid rdpmc index");
+	    }
+	}
+    }
+  return 0;
+}
+
+clib_error_t *
+intel_config_dispatch_wrapper (perfmon_bundle_t *b,
+			       vlib_node_function_t **dispatch_wrapper)
+{
+  clib_error_t *err = 0;
+  if ((err = read_mmap_indexes (b)) != 0)
+    return err;
+
+  (*dispatch_wrapper) = perfmon_dispatch_wrappers[b->n_events];
+  return 0;
+}
+
 #define foreach_n_events                                                      \
   _ (1) _ (2) _ (3) _ (4) _ (5) _ (6) _ (7) _ (8) _ (9) _ (10) _ (11) _ (12)
 
diff --git a/src/plugins/perfmon/intel/dispatch_wrapper.h b/src/plugins/perfmon/intel/dispatch_wrapper.h
new file mode 100644
index 00000000000..bcf4885d54d
--- /dev/null
+++ b/src/plugins/perfmon/intel/dispatch_wrapper.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2022 Arm and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+clib_error_t *
+intel_config_dispatch_wrapper (perfmon_bundle_t *b,
+			       vlib_node_function_t **dispatch_wrapper);
diff --git a/src/plugins/perfmon/intel/uncore.c b/src/plugins/perfmon/intel/uncore.c
index 01579964bea..ac5580a3e62 100644
--- a/src/plugins/perfmon/intel/uncore.c
+++ b/src/plugins/perfmon/intel/uncore.c
@@ -220,4 +220,5 @@ PERFMON_REGISTER_SOURCE (intel_uncore) = {
   .n_events = INTEL_UNCORE_N_EVENTS,
   .init_fn = intel_uncore_init,
   .format_config = format_intel_core_config,
+  .bundle_support = intel_bundle_supported,
 };
diff --git a/src/plugins/perfmon/perfmon.c b/src/plugins/perfmon/perfmon.c
index cc978888f02..0643384957e 100644
--- a/src/plugins/perfmon/perfmon.c
+++ b/src/plugins/perfmon/perfmon.c
@@ -213,33 +213,6 @@ error:
   return err;
 }
 
-static_always_inline u32
-perfmon_mmap_read_index (const struct perf_event_mmap_page *mmap_page)
-{
-  u32 idx;
-  u32 seq;
-
-  /* See documentation in /usr/include/linux/perf_event.h, for more details
-   * but the 2 main important things are:
-   *  1) if seq != mmap_page->lock, it means the kernel is currently updating
-   *     the user page and we need to read it again
-   *  2) if idx == 0, it means the perf event is currently turned off and we
-   *     just need to read the kernel-updated 'offset', otherwise we must also
-   *     add the current hw value (hence rdmpc) */
-  do
-    {
-      seq = mmap_page->lock;
-      CLIB_COMPILER_BARRIER ();
-
-      idx = mmap_page->index;
-
-      CLIB_COMPILER_BARRIER ();
-    }
-  while (mmap_page->lock != seq);
-
-  return idx;
-}
-
 clib_error_t *
 perfmon_start (vlib_main_t *vm, perfmon_bundle_t *b)
 {
@@ -266,27 +239,17 @@ perfmon_start (vlib_main_t *vm, perfmon_bundle_t *b)
     }
   if (b->active_type == PERFMON_BUNDLE_TYPE_NODE)
     {
-      for (int i = 0; i < vec_len (pm->thread_runtimes); i++)
+      vlib_node_function_t *dispatch_wrapper = NULL;
+      err = b->src->config_dispatch_wrapper (b, &dispatch_wrapper);
+      if (err || !dispatch_wrapper)
 	{
-	  perfmon_thread_runtime_t *tr;
-	  tr = vec_elt_at_index (pm->thread_runtimes, i);
-
-	  for (int j = 0; j < b->n_events; j++)
-	    {
-	      tr->indexes[j] = perfmon_mmap_read_index (tr->mmap_pages[j]);
-
-	      /* if a zero index is returned generate error */
-	      if (!tr->indexes[j])
-		{
-		  perfmon_reset (vm);
-		  return clib_error_return (0, "invalid rdpmc index");
-		}
-	    }
+	  perfmon_reset (vm);
+	  return err;
 	}
 
       for (int i = 0; i < vlib_get_n_threads (); i++)
-	vlib_node_set_dispatch_wrapper (
-	  vlib_get_main_by_index (i), perfmon_dispatch_wrappers[b->n_events]);
+	vlib_node_set_dispatch_wrapper (vlib_get_main_by_index (i),
+					dispatch_wrapper);
     }
   pm->sample_time = vlib_time_now (vm);
   pm->is_running = 1;
@@ -324,53 +287,6 @@ perfmon_stop (vlib_main_t *vm)
   return 0;
 }
 
-static_always_inline u8
-is_enough_counters (perfmon_bundle_t *b)
-{
-  u8 bl[PERFMON_EVENT_TYPE_MAX];
-  u8 cpu[PERFMON_EVENT_TYPE_MAX];
-
-  clib_memset (&bl, 0, sizeof (bl));
-  clib_memset (&cpu, 0, sizeof (cpu));
-
-  /* how many does this uarch support */
-  if (!clib_get_pmu_counter_count (&cpu[PERFMON_EVENT_TYPE_FIXED],
-				   &cpu[PERFMON_EVENT_TYPE_GENERAL]))
-    return 0;
-
-  /* how many does the bundle require */
-  for (u16 i = 0; i < b->n_events; i++)
-    {
-      /* if source allows us to identify events, otherwise assume general */
-      if (b->src->get_event_type)
-	bl[b->src->get_event_type (b->events[i])]++;
-      else
-	bl[PERFMON_EVENT_TYPE_GENERAL]++;
-    }
-
-  /* consciously ignoring pseudo events here */
-  return cpu[PERFMON_EVENT_TYPE_GENERAL] >= bl[PERFMON_EVENT_TYPE_GENERAL] &&
-	 cpu[PERFMON_EVENT_TYPE_FIXED] >= bl[PERFMON_EVENT_TYPE_FIXED];
-}
-
-static_always_inline u8
-is_bundle_supported (perfmon_bundle_t *b)
-{
-  perfmon_cpu_supports_t *supports = b->cpu_supports;
-
-  if (!is_enough_counters (b))
-    return 0;
-
-  if (!b->cpu_supports)
-    return 1;
-
-  for (int i = 0; i < b->n_cpu_supports; ++i)
-    if (supports[i].cpu_supports ())
-      return 1;
-
-  return 0;
-}
-
 static clib_error_t *
 perfmon_init (vlib_main_t *vm)
 {
@@ -413,7 +329,7 @@ perfmon_init (vlib_main_t *vm)
 	}
 
       b->src = (perfmon_source_t *) p[0];
-      if (!is_bundle_supported (b))
+      if (b->src->bundle_support && !b->src->bundle_support (b))
 	{
 	  log_debug ("skipping bundle '%s' - not supported", b->name);
 	  b = b->next;
diff --git a/src/plugins/perfmon/perfmon.h b/src/plugins/perfmon/perfmon.h
index fa15ef63aca..f08cc7a5dcb 100644
--- a/src/plugins/perfmon/perfmon.h
+++ b/src/plugins/perfmon/perfmon.h
@@ -23,7 +23,9 @@
 #include <vppinfra/cpu.h>
 #include <vlib/vlib.h>
 
+#if defined(__x86_64__)
 #define PERF_MAX_EVENTS 12 /* 4 fixed and 8 programable on ICX */
+#endif
 
 typedef enum
 {
@@ -86,11 +88,14 @@ typedef struct
 } perfmon_instance_type_t;
 
 struct perfmon_source;
-extern vlib_node_function_t *perfmon_dispatch_wrappers[PERF_MAX_EVENTS + 1];
+typedef struct perfmon_bundle perfmon_bundle_t;
 
 typedef clib_error_t *(perfmon_source_init_fn_t) (vlib_main_t *vm,
 						  struct perfmon_source *);
 typedef perfmon_event_type_t (perfmon_source_get_event_type) (u32 event);
+typedef u8 (perfmon_source_bundle_support_t) (perfmon_bundle_t *);
+typedef clib_error_t *(perfmon_source_config_dispatch_wrapper_t) (
+  perfmon_bundle_t *b, vlib_node_function_t **dispatch_wrapper);
 
 typedef struct perfmon_source
 {
@@ -103,10 +108,10 @@ typedef struct perfmon_source
   format_function_t *format_config;
   perfmon_source_get_event_type *get_event_type;
   perfmon_source_init_fn_t *init_fn;
+  perfmon_source_bundle_support_t *bundle_support;
+  perfmon_source_config_dispatch_wrapper_t *config_dispatch_wrapper;
 } perfmon_source_t;
 
-struct perfmon_bundle;
-
 typedef clib_error_t *(perfmon_bundle_init_fn_t) (vlib_main_t *vm,
 						  struct perfmon_bundle *);