From b97fb4cfdf3d33ed26b78d5d30c4284ae26e8d74 Mon Sep 17 00:00:00 2001
From: Kondo Takeo <takeoverjp@gmail.com>
Date: Wed, 17 Feb 2021 23:02:27 +0900
Subject: [PATCH] Issue: #96 - Garbage collect inodeproc once every 50 ui
 refresh as default.

- Reduce default frequency to avoid performance issue.
- The frequency of it can be modified with `-g` option
  and can be disabled with `-g 0`.
---
 doc/nethogs.8      |  4 ++++
 src/inode2prog.cpp |  3 ++-
 src/main.cpp       | 16 ++++++++++++++--
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/doc/nethogs.8 b/doc/nethogs.8
index efa5f1e..7c987b7 100644
--- a/doc/nethogs.8
+++ b/doc/nethogs.8
@@ -19,6 +19,7 @@ nethogs \- Net top tool grouping bandwidth per process
 .RB [ "\-l" ]
 .RB [ "\-f filter" ]
 .RB [ "\-C" ]
+.RB [ "\-g period" ]
 .RI [device(s)]
 .SH DESCRIPTION
 NetHogs is a small 'net top' tool. Instead of breaking the traffic down per protocol or per subnet, like most such tools do, it groups bandwidth by process - and does not rely on a special kernel module to be loaded. So if there's suddenly a lot of network traffic, you can fire up NetHogs and immediately see which PID is causing this, and if it's some kind of spinning process, kill it.
@@ -61,6 +62,9 @@ monitor all devices, even loopback/stopped ones.
 \fB-C\fP
 capture TCP and UDP.
 .TP
+\fB-g\fP
+garbage collection period in number of refresh. default is 50.
+.TP
 \fB-f\fP
 EXPERIMENTAL: specify string pcap filter (like tcpdump). This may be removed or changed in a future version.
 .TP
diff --git a/src/inode2prog.cpp b/src/inode2prog.cpp
index 17f59b4..a370b46 100644
--- a/src/inode2prog.cpp
+++ b/src/inode2prog.cpp
@@ -235,7 +235,8 @@ static quad_t get_ms() {
 static void get_pids(std::set<pid_t> *pids) {
   DIR *proc = opendir("/proc");
   if (proc == 0) {
-    std::cerr << "Error reading /proc, needed to get inode-to-pid-mapping" << std::endl;
+    std::cerr << "Error reading /proc, needed to get inode-to-pid-mapping"
+              << std::endl;
     exit(1);
   }
   dirent *entry;
diff --git a/src/main.cpp b/src/main.cpp
index d32b8d8..52964ce 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -46,6 +46,8 @@ static void help(bool iserror) {
   output << "		-a : monitor all devices, even loopback/stopped "
             "ones.\n";
   output << "		-C : capture TCP and UDP.\n";
+  output << "		-g : garbage collection period in number of refresh. "
+            "default is 50.\n";
   output << "		-f : EXPERIMENTAL: specify string pcap filter (like "
             "tcpdump)."
             " This may be removed or changed in a future version.\n";
@@ -140,9 +142,10 @@ int main(int argc, char **argv) {
   int promisc = 0;
   bool all = false;
   char *filter = NULL;
+  int garbage_collection_period = 50;
 
   int opt;
-  while ((opt = getopt(argc, argv, "Vhbtpsd:v:c:laf:C")) != -1) {
+  while ((opt = getopt(argc, argv, "Vhbtpsd:v:c:laf:Cg:")) != -1) {
     switch (opt) {
     case 'V':
       versiondisplay();
@@ -184,6 +187,9 @@ int main(int argc, char **argv) {
     case 'C':
       catchall = true;
       break;
+    case 'g':
+      garbage_collection_period = (time_t)atoi(optarg);
+      break;
     default:
       help(true);
       exit(EXIT_FAILURE);
@@ -294,6 +300,7 @@ int main(int argc, char **argv) {
   struct dpargs *userdata = (dpargs *)malloc(sizeof(struct dpargs));
 
   // Main loop:
+  int refresh_count = 0;
   while (1) {
     bool packets_read = false;
 
@@ -322,7 +329,12 @@ int main(int argc, char **argv) {
         ui_tick();
       }
       do_refresh();
-      garbage_collect_processes();
+      ++refresh_count;
+
+      if ((garbage_collection_period > 0) &&
+          (refresh_count % garbage_collection_period == 0)) {
+        garbage_collect_processes();
+      }
     }
 
     // if not packets, do a select() until next packet