top: limit task cpu % based on total number of threads

Everyone has either accepted this potential distortion
or patched top to eliminate it. Now, the time has come
to regain some consistency when calculating that %CPU.

We'll now limit such values to: 100.0 * total threads.
And, it took way too long to address this little flaw.

(now that we know a '.' + 2 spaces is squeezed to one)
(everything's perfectly justified, but it's just luck)

Reference(s):
http://www.freelists.org/post/procps/top-regression-reports
http://www.freelists.org/post/procps/top-regression-reports,1

Signed-off-by: Jim Warner <james.warner@comcast.net>

diff --git a/top/top.1 b/top/top.1
index c914e771f89fff9efb6622f8fed8193a29c94186..fb9d740c2373c510e7e0a6a876c75d5f954d6c37 100644 (file)
--- a/top/top.1
+++ b/top/top.1
@@ -454,9 +454,15 @@ Such fields can, however, be scaled differently via the 'e' \*(CI.
  1.\fB %CPU \*(Em \*(PU Usage \fR
 The task's share of the elapsed \*(PU time since the last screen update,
 expressed as a percentage of total \*(PU time.
-In a true SMP environment, if 'Irix mode' is \*F, \*(We will operate
-in 'Solaris mode' where a task's \*(Pu usage will be divided by the total
-number of \*(PUs.
+
+In a true SMP environment, if a process is multi-threaded and \*(We is
+\fInot\fR operating in Threads mode, amounts greater than 100% may be
+reported.
+You toggle Threads mode with the 'H' \*(CI.
+
+Also for multi-processor environments, if 'Irix mode' is \*F, \*(We
+will operate in 'Solaris mode' where a task's \*(Pu usage will be
+divided by the total number of \*(PUs.
 You toggle 'Irix/Solaris' modes with the 'I' \*(CI.
 
 .TP 4

diff --git a/top/top.c b/top/top.c
index 3d35ab2200e1fc6ca123d55ed7a1377aa68eceb2..c9678f96c553fdf189f9646c377bef53dcb45864 100644 (file)
--- a/top/top.c
+++ b/top/top.c
@@ -4631,6 +4631,9 @@ static const char *task_show (const WIN_t *q, const proc_t *p) {
             break;
          case P_CPU:
          {  float u = (float)p->pcpu * Frame_etscale;
+            /* process can't use more %cpu than number of threads it has
+             ( thanks Jaromir Capik <jcapik@redhat.com> ) */
+            if (u > 100.0 * p->nlwp) u = 100.0 * p->nlwp;
             if (u > Cpu_pmax) u = Cpu_pmax;
             cp = scale_pcnt(u, W, Jn);
          }