From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 5 Mar 2022 03:21:38 +0000 (-0800)
Subject: %CPU can exceed 100 on GNU/Linux
X-Git-Tag: emacs-29.0.90~2007
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=b19ec1be3c35b0ec231282ab51d0b320e2967052;p=emacs.git

%CPU can exceed 100 on GNU/Linux

* src/sysdep.c (system_process_attributes) [GNU_LINUX]:
CPU usage can exceed 100% on a multicore platform when Emacs is
not entirely single-threaded.
---

diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi
index d338d59a814..ed07c1cbf70 100644
--- a/doc/lispref/processes.texi
+++ b/doc/lispref/processes.texi
@@ -2382,8 +2382,9 @@ occupied by the process in the machine's physical memory.
 
 @item pcpu
 The percentage of the CPU time used by the process since it started.
-The corresponding @var{value} is a floating-point number between 0 and
-100.
+The corresponding @var{value} is a nonnegative floating-point number.
+Although in theory the number can exceed 100 on a multicore platform,
+it is usually less than 100 because Emacs is typically single-threaded.
 
 @item pmem
 The percentage of the total physical memory installed on the machine
diff --git a/src/sysdep.c b/src/sysdep.c
index 28d32c77c63..c9101f94818 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -3487,8 +3487,6 @@ system_process_attributes (Lisp_Object pid)
 	  attrs = Fcons (Fcons (Qetime, make_lisp_time (telapsed)), attrs);
 	  us_time = time_from_jiffies (u_time + s_time, clocks_per_sec);
 	  pcpu = timespectod (us_time) / timespectod (telapsed);
-	  if (pcpu > 1.0)
-	    pcpu = 1.0;
 	  attrs = Fcons (Fcons (Qpcpu, make_float (100 * pcpu)), attrs);
 	  pmem = 4.0 * 100 * rss / procfs_get_total_memory ();
 	  if (pmem > 100)