Reduce the number of instrumenting files. If profiling level is INFO,…

… only process 0 logs its runtime. If profiling level is TRACE, each process will create a file.

src/simulation/logging.rs

@@ -2,6 +2,7 @@ use std::io;
 use std::path::PathBuf;
 
 use tracing::level_filters::LevelFilter;
+use tracing::Level;
 use tracing_appender::non_blocking::WorkerGuard;
 use tracing_appender::{non_blocking, rolling};
 use tracing_subscriber::fmt;
@@ -25,16 +26,7 @@ pub fn init_logging(config: &Config, part: u32) -> (Option<WorkerGuard>, Option<
     let file_discriminant = part.to_string();
     let dir = PathBuf::from(&config.output().output_dir);
 
-    let (csv_layer, guard) = if let Profiling::CSV(level) = config.output().profiling {
-        let duration_dir = dir.join("instrument");
-        let duration_file_name = format!("instrument_process_{file_discriminant}.csv");
-        let duration_path = duration_dir.join(duration_file_name);
-        let (layer, writer_guard) =
-            SpanDurationToCSVLayer::new(&duration_path, level.create_tracing_level());
-        (Some(layer), Some(writer_guard))
-    } else {
-        (None, None)
-    };
+    let (csv_layer, guard) = init_tracing(config, part, &file_discriminant, &dir);
     let (log_layer, log_guard) = if Logging::Info == config.output().logging {
         let log_file_name = format!("log_process_{file_discriminant}.txt");
         let log_file_appender = rolling::never(&dir, log_file_name);
@@ -63,3 +55,29 @@ pub fn init_logging(config: &Config, part: u32) -> (Option<WorkerGuard>, Option<
     tracing::subscriber::set_global_default(collector).expect("Unable to set a global collector");
     (log_guard, guard)
 }
+
+fn init_tracing(
+    config: &Config,
+    part: u32,
+    file_discriminant: &String,
+    dir: &PathBuf,
+) -> (Option<SpanDurationToCSVLayer>, Option<WriterGuard>) {
+    // if we set profiling at all and if profiling is set to level trace, then each process creates an instrumenting file
+    // if profiling level is set to INFO, only process 0 creates an instrument files. This is important if we run on a lot of
+    // processes, because then we spent a lot of computing time on creating instrument files for each process.
+    let (csv_layer, guard) = if let Profiling::CSV(level_string) = config.output().profiling {
+        let level = level_string.create_tracing_level();
+        if level.eq(&Level::INFO) && part == 0 || level.eq(&Level::TRACE) {
+            let duration_dir = dir.join("instrument");
+            let duration_file_name = format!("instrument_process_{file_discriminant}.csv");
+            let duration_path = duration_dir.join(duration_file_name);
+            let (layer, writer_guard) = SpanDurationToCSVLayer::new(&duration_path, level);
+            (Some(layer), Some(writer_guard))
+        } else {
+            (None, None)
+        }
+    } else {
+        (None, None)
+    };
+    (csv_layer, guard)
+}