From 1b3eef72f71bbef70916f74dec6dceca252b4e51 Mon Sep 17 00:00:00 2001
From: Michael Mueller <michael.mueller@uos.de>
Date: Mon, 7 Aug 2023 18:18:58 +0200
Subject: [PATCH] Example for using the low-level interface for PMCs.

---
 repos/mml/src/app/pfm_test/main.cc   | 109 +++++++++++++++++++++++++++
 repos/mml/src/app/pfm_test/target.mk |   4 +
 2 files changed, 113 insertions(+)
 create mode 100644 repos/mml/src/app/pfm_test/main.cc
 create mode 100644 repos/mml/src/app/pfm_test/target.mk

diff --git a/repos/mml/src/app/pfm_test/main.cc b/repos/mml/src/app/pfm_test/main.cc
new file mode 100644
index 0000000000..98953cf817
--- /dev/null
+++ b/repos/mml/src/app/pfm_test/main.cc
@@ -0,0 +1,109 @@
+/**
+ * @file main.cc
+ * @author Michael Müller (michael.mueller@uos.de)
+ * @brief Some Tests for using Performance Counters with libpfm and the NOVA syscalls
+ * @version 0.1
+ * @date 2022-12-14
+ * 
+ * @copyright Copyright (c) 2022
+ * 
+ */
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+#include <thread>
+#include <chrono>
+
+#include <nova/syscall-generic.h>
+#include <nova/syscalls.h>
+
+extern "C" {
+#include <perfmon/err.h>
+#include <perfmon/pfmlib.h>
+}
+
+int main(void)
+{
+    pfm_pmu_info_t pinfo;
+    pfm_pmu_encode_arg_t e;
+    pfm_event_info_t info;
+    int ret;
+
+    ret = pfm_initialize();
+    if (ret != PFM_SUCCESS) {
+        std::cerr << "cannot initialize libpfm: " << pfm_strerror(ret) << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    memset(&pinfo, 0, sizeof(pfm_pmu_info_t));
+
+    ret = pfm_get_pmu_info(PFM_PMU_AMD64_FAM17H_ZEN1, &pinfo);
+    if (ret != PFM_SUCCESS)
+    {
+        std::cerr << "Failed to find PMU" << std::endl;
+        return -EXIT_FAILURE;
+    }
+
+    if (!pinfo.is_present) {
+        std::cerr << "No AMD PMU present" << std::endl;
+        return -EXIT_FAILURE;
+    }
+
+    memset(&e, 0, sizeof(e));
+
+    char *fqstr = nullptr;
+    e.fstr = &fqstr;
+
+    do
+    {
+        ret = pfm_get_os_event_encoding("ITLB_RELOADS", PFM_PLM0 | PFM_PLM3, PFM_OS_NONE, &e);
+        if (ret == PFM_ERR_TOOSMALL) {
+            free(e.codes);
+            e.codes = NULL;
+            e.count = 0;
+            continue;
+        } else {
+            std::cerr << "No such event" << std::endl;
+            return EXIT_FAILURE;
+        }
+    } while (ret != PFM_SUCCESS);
+
+    memset(&info, 0, sizeof(info));
+
+    ret = pfm_get_event_info(e.idx, PFM_OS_NONE, &info);
+    if (ret) {
+        std::cerr << "Failed to get event info" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    std::cout << "Event found : " << fqstr << std::endl;
+    std::cout << "Code : " << info.code << std::endl;
+
+    Nova::uint8_t rc = 0;
+    Nova::mword_t umask = 0x6;
+    Nova::mword_t flags = 0x0;
+
+    if ((rc = Nova::hpc_ctrl(Nova::HPC_SETUP, 0, 1, info.code, umask, flags)) != Nova::NOVA_OK) {
+        std::cerr << "Failed to setup HPC 0 for event" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    if ((rc = Nova::hpc_start(0, 1))) {
+        std::cerr << "Failed to start counter" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    std::cout << "Successfully set up hardware performance counter 0" << std::endl;
+
+    for (;;) {
+        std::this_thread::sleep_for(std::chrono::milliseconds(100));
+        Nova::mword_t value;
+        if ((rc = Nova::hpc_read(0, 1, value)) != Nova::NOVA_OK) {
+            std::cerr << "Failed to read HPC" << std::endl;
+            return EXIT_FAILURE;
+        }
+        std::cout << "Counter value: " << value << std::endl;
+    }
+
+    return EXIT_SUCCESS;
+}
\ No newline at end of file
diff --git a/repos/mml/src/app/pfm_test/target.mk b/repos/mml/src/app/pfm_test/target.mk
new file mode 100644
index 0000000000..5f61b6d5ed
--- /dev/null
+++ b/repos/mml/src/app/pfm_test/target.mk
@@ -0,0 +1,4 @@
+TARGET = pfm_test
+SRC_CC = main.cc 
+LIBS += base posix libm libc stdcxx libpfm4 
+CC_OPT += -Wno-error -fpermissive -Wno-error=conversion
\ No newline at end of file