db_bench_tool: basic sys infos for FreeBSD. (#8169)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8169

Reviewed By: riversand963

Differential Revision: D27672457

Pulled By: ajkr

fbshipit-source-id: b40a7ad5d09a754154f28c2574ef9f77c8a131bb

tools/db_bench_tool.cc

@@ -23,6 +23,9 @@
 #include <mach/mach_host.h>
 #include <sys/sysctl.h>
 #endif
+#ifdef __FreeBSD__
+#include <sys/sysctl.h>
+#endif
 #include <atomic>
 #include <cinttypes>
 #include <condition_variable>
@@ -2638,7 +2641,7 @@ class Benchmark {
     fprintf(stderr, "RocksDB:    version %d.%d\n",
             kMajorVersion, kMinorVersion);
 
-#if defined(__linux) || defined(__APPLE__)
+#if defined(__linux) || defined(__APPLE__) || defined(__FreeBSD__)
     time_t now = time(nullptr);
     char buf[52];
     // Lint complains about ctime() usage, so replace it with ctime_r(). The
@@ -2696,6 +2699,19 @@ class Benchmark {
       fprintf(stderr, "CPU:        %d * %s\n", h.max_cpus, cpu_type.c_str());
       fprintf(stderr, "CPUCache:   %s\n", cache_size.c_str());
     }
+#elif defined(__FreeBSD__)
+    int ncpus;
+    size_t len = sizeof(ncpus);
+    int mib[2] = {CTL_HW, HW_NCPU};
+    if (sysctl(mib, 2, &ncpus, &len, nullptr, 0) == 0) {
+      char cpu_type[16];
+      len = sizeof(cpu_type) - 1;
+      mib[1] = HW_MACHINE;
+      if (sysctl(mib, 2, cpu_type, &len, nullptr, 0) == 0) cpu_type[len] = 0;
+
+      fprintf(stderr, "CPU:        %d * %s\n", ncpus, cpu_type);
+      // no programmatic way to get the cache line size except on PPC
+    }
 #endif
 #endif
   }