feat: add --perfmon-trace-file and -o perfmon_trace_file

doc/dwarfs.md

@@ -156,8 +156,12 @@ options:
 - `-o perfmon=`*name*:
   Enable performance monitoring for the list of comma-separated components.
   This option is only available if the project was built with performance
-  monitoring enabled. Available components include `fuse`, `filesystem_v2`
+  monitoring enabled. Available components include `fuse`, `filesystem_v2`,
-  and `inode_reader_v2`.
+  `inode_reader_v2` and `block_cache`.
+
+- `-o perfmon_trace=`*file*:
+  Write JSON trace data for all components enabled by `--perfmon` to this
+  file when the process exits.
 
 - `--man`:
   If the project was built with support for built-in manual pages, this

doc/dwarfsextract.md

@@ -93,8 +93,12 @@ to disk:
 - `--perfmon=`*name*:
   Enable performance monitoring for the list of comma-separated components.
   This option is only available if the project was built with performance
-  monitoring enabled. Available components include `fuse`, `filesystem_v2`
+  monitoring enabled. Available components include `fuse`, `filesystem_v2`,
-  and `inode_reader_v2`.
+  `inode_reader_v2` and `block_cache`.
+
+- `--perfmon-trace=`*file*:
+  Write JSON trace data for all components enabled by `--perfmon` to this
+  file when the process exits.
 
 - `-h`, `--help`:
   Show program help, including option defaults.

src/dwarfs_main.cpp

@@ -159,7 +159,8 @@ struct options {
   char const* cache_tidy_interval_str{nullptr}; // TODO: const?? -> use string?
   char const* cache_tidy_max_age_str{nullptr};  // TODO: const?? -> use string?
 #if DWARFS_PERFMON_ENABLED
-  char const* perfmon_enabled_str{nullptr}; // TODO: const?? -> use string?
+  char const* perfmon_enabled_str{nullptr};    // TODO: const?? -> use string?
+  char const* perfmon_trace_file_str{nullptr}; // TODO: const?? -> use string?
 #endif
   int enable_nlink{0};
   int readonly{0};
@@ -237,6 +238,7 @@ constexpr struct ::fuse_opt dwarfs_opts[] = {
     DWARFS_OPT("no_cache_files", cache_files, 0),
 #if DWARFS_PERFMON_ENABLED
     DWARFS_OPT("perfmon=%s", perfmon_enabled_str, 0),
+    DWARFS_OPT("perfmon_trace=%s", perfmon_trace_file_str, 0),
 #endif
     FUSE_OPT_END};
 
@@ -1041,6 +1043,7 @@ void usage(std::ostream& os, std::filesystem::path const& progname) {
      << "    -o tidy_max_age=TIME   tidy blocks after this time (10m)\n"
 #if DWARFS_PERFMON_ENABLED
      << "    -o perfmon=name[,...]  enable performance monitor\n"
+     << "    -o perfmon_trace=FILE  write performance monitor trace file\n"
 #endif
 #ifdef DWARFS_BUILTIN_MANPAGE
      << "    --man                  show manual page and exit\n"
@@ -1274,15 +1277,21 @@ void load_filesystem(dwarfs_userdata& userdata) {
   }
 
   std::unordered_set<std::string> perfmon_enabled;
+  std::optional<std::filesystem::path> perfmon_trace_file;
 #if DWARFS_PERFMON_ENABLED
   if (opts.perfmon_enabled_str) {
     folly::splitTo<std::string>(
         ',', opts.perfmon_enabled_str,
         std::inserter(perfmon_enabled, perfmon_enabled.begin()));
   }
+  if (opts.perfmon_trace_file_str) {
+    perfmon_trace_file = userdata.iol.os->canonical(std::filesystem::path(
+        reinterpret_cast<char8_t const*>(opts.perfmon_trace_file_str)));
+  }
 #endif
 
-  userdata.perfmon = performance_monitor::create(perfmon_enabled);
+  userdata.perfmon = performance_monitor::create(
+      perfmon_enabled, userdata.iol.file, perfmon_trace_file);
 
   PERFMON_EXT_PROXY_SETUP(userdata, userdata.perfmon, "fuse")
   PERFMON_EXT_TIMER_SETUP(userdata, op_init)

src/dwarfsextract_main.cpp

@@ -59,7 +59,7 @@ constexpr std::string_view kDash{"-"};
 } // namespace
 
 int dwarfsextract_main(int argc, sys_char** argv, iolayer const& iol) {
-  sys_string filesystem, output;
+  sys_string filesystem, output, trace_file;
   std::string format, cache_size_str, image_offset;
   logger_options logopts;
 #if DWARFS_PERFMON_ENABLED
@@ -103,6 +103,9 @@ int dwarfsextract_main(int argc, sys_char** argv, iolayer const& iol) {
     ("perfmon",
         po::value<std::string>(&perfmon_str),
         "enable performance monitor")
+    ("perfmon-trace",
+        po_sys_value<sys_string>(&trace_file),
+        "write performance monitor trace file")
 #endif
     ;
   // clang-format on
@@ -152,15 +155,19 @@ int dwarfsextract_main(int argc, sys_char** argv, iolayer const& iol) {
     fsopts.metadata.enable_nlink = true;
 
     std::unordered_set<std::string> perfmon_enabled;
+    std::optional<std::filesystem::path> perfmon_trace_file;
 #if DWARFS_PERFMON_ENABLED
     if (!perfmon_str.empty()) {
       folly::splitTo<std::string>(
           ',', perfmon_str,
           std::inserter(perfmon_enabled, perfmon_enabled.begin()));
     }
+    if (!trace_file.empty()) {
+      perfmon_trace_file = iol.os->canonical(trace_file);
+    }
 #endif
-    std::shared_ptr<performance_monitor> perfmon =
+    std::shared_ptr<performance_monitor> perfmon = performance_monitor::create(
-        performance_monitor::create(perfmon_enabled);
+        perfmon_enabled, iol.file, perfmon_trace_file);
 
     auto fs_path = iol.os->canonical(filesystem);