eden top sort by time

Summary: When processes make FUSE calls, put them at the top of the list of processes. Also resolved an error where the curses library would refresh improperly and draw white lines across the screen.

Reviewed By: chadaustin

Differential Revision: D16194691

fbshipit-source-id: 9ed0515786d53181b7c3e9497c5d6ebc92f51682

eden/cli/top.py

@@ -28,6 +28,9 @@ class Top:
     def __init__(self):
         self.running = False
         self.ephemeral = False
+
+        # Maps (mount, name) pairs to another dictionary,
+        # which tracks the # of FUSE calls per PID
         self.processes: DefaultDict[
             Tuple[bytes, bytes], DefaultDict[int, int]
         ] = collections.defaultdict(lambda: collections.defaultdict(lambda: 0))
@@ -81,11 +84,17 @@ class Top:
                 name = names_by_pid.get(pid, b"<unknown>")
                 process = (mount, name)
 
-                self.processes[process][pid] += calls.count
+                calls_by_pid = self.processes[process]
+                # Delete, increment, and re-add to end of OrderedDict
+                del self.processes[process]
+                calls_by_pid[pid] += calls.count
+                self.processes[process] = calls_by_pid
 
     def update_rows(self):
         self.rows = []
-        for (mount, name), calls_per_pid in self.processes.items():
+
+        ordered_processes = reversed(list(self.processes.items()))
+        for (mount, name), calls_per_pid in ordered_processes:
             name = format_name(name)
             mount = format_mount(mount)
             calls = sum(calls_per_pid.values())
@@ -102,8 +111,7 @@ class Top:
         return sum(c[0] for c in ls)
 
     def render(self, stdscr):
-        stdscr.noutrefresh()
-        stdscr.erase()
+        stdscr.clear()
 
         self.render_top_bar(stdscr)
         # TODO: daemon memory/inode stats on line 2
@@ -111,7 +119,7 @@ class Top:
         self.render_column_titles(stdscr)
         self.render_rows(stdscr)
 
-        curses.doupdate()
+        stdscr.refresh()
 
     def render_top_bar(self, stdscr):
         TITLE = "eden top"