library: tweak those system cpu statistics, <stat> api

This patch may be a little misleading in terms of size
since most of the changes just reorder a little logic.
The most significant changes involve two GUEST values.

My original implementation excluded such tics from the
TOTAL calculation and, therefore, the BUSY figure too.

That decision was erroneously based on some code found
in ./kernel/sched/cputime.c which in hindsight applies
only to processes, not those system level cpu figures.

[ another likely oops classified STOLEN tics as IDLE ]

So, this patch attempts to bring those SUM values into
better agreement with the calculations performed for a
root cgroup (see ./kernel/cgroup/rstat.c source file).

[ we differ from those above in that we also include ]
[ the IDLE plus IOWAIT tics in our TOTAL calculation ]

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

diff --git a/proc/stat.c b/proc/stat.c
index ff138adc1f65a5763ef09b42855bba6d8d3b0cf0..5efcc03e1b1ee90f557813b8420a39adb711c188 100644 (file)
--- a/proc/stat.c
+++ b/proc/stat.c
@@ -67,7 +67,7 @@
 
 struct stat_jifs {
     unsigned long long user, nice, system, idle, iowait, irq, sirq, stolen, guest, gnice;
-    unsigned long long xtot, xbsy, xidl, xusr, xsys;
+    unsigned long long xusr, xsys, xidl, xbsy, xtot;
 };
 
 struct stat_data {
@@ -192,17 +192,17 @@ TICsetH(TIC_DELTA_STOLEN,         sl_int,   stolen)
 TICsetH(TIC_DELTA_GUEST,          sl_int,   guest)
 TICsetH(TIC_DELTA_GUEST_NICE,     sl_int,   gnice)
 
-TIC_set(TIC_SUM_TOTAL,            ull_int,  xtot)
-TIC_set(TIC_SUM_IDLE,             ull_int,  xidl)
 TIC_set(TIC_SUM_USER,             ull_int,  xusr)
-TIC_set(TIC_SUM_BUSY,             ull_int,  xbsy)
 TIC_set(TIC_SUM_SYSTEM,           ull_int,  xsys)
+TIC_set(TIC_SUM_IDLE,             ull_int,  xidl)
+TIC_set(TIC_SUM_BUSY,             ull_int,  xbsy)
+TIC_set(TIC_SUM_TOTAL,            ull_int,  xtot)
 
-TICsetH(TIC_SUM_DELTA_TOTAL,      sl_int,   xtot)
-TICsetH(TIC_SUM_DELTA_IDLE,       sl_int,   xidl)
 TICsetH(TIC_SUM_DELTA_USER,       sl_int,   xusr)
-TICsetH(TIC_SUM_DELTA_BUSY,       sl_int,   xbsy)
 TICsetH(TIC_SUM_DELTA_SYSTEM,     sl_int,   xsys)
+TICsetH(TIC_SUM_DELTA_IDLE,       sl_int,   xidl)
+TICsetH(TIC_SUM_DELTA_BUSY,       sl_int,   xbsy)
+TICsetH(TIC_SUM_DELTA_TOTAL,      sl_int,   xtot)
 
 SYS_set(SYS_CTX_SWITCHES,         ul_int,   ctxt)
 SYS_set(SYS_INTERRUPTS,           ul_int,   intr)
@@ -329,17 +329,17 @@ static struct {
   { RS(TIC_DELTA_GUEST),         QS(sl_int),   TS(sl_int)  },
   { RS(TIC_DELTA_GUEST_NICE),    QS(sl_int),   TS(sl_int)  },
 
-  { RS(TIC_SUM_TOTAL),           QS(ull_int),  TS(ull_int) },
-  { RS(TIC_SUM_IDLE),            QS(ull_int),  TS(ull_int) },
   { RS(TIC_SUM_USER),            QS(ull_int),  TS(ull_int) },
-  { RS(TIC_SUM_BUSY),            QS(ull_int),  TS(ull_int) },
   { RS(TIC_SUM_SYSTEM),          QS(ull_int),  TS(ull_int) },
+  { RS(TIC_SUM_IDLE),            QS(ull_int),  TS(ull_int) },
+  { RS(TIC_SUM_BUSY),            QS(ull_int),  TS(ull_int) },
+  { RS(TIC_SUM_TOTAL),           QS(ull_int),  TS(ull_int) },
 
-  { RS(TIC_SUM_DELTA_TOTAL),     QS(sl_int),   TS(sl_int)  },
-  { RS(TIC_SUM_DELTA_IDLE),      QS(sl_int),   TS(sl_int)  },
   { RS(TIC_SUM_DELTA_USER),      QS(sl_int),   TS(sl_int)  },
-  { RS(TIC_SUM_DELTA_BUSY),      QS(sl_int),   TS(sl_int)  },
   { RS(TIC_SUM_DELTA_SYSTEM),    QS(sl_int),   TS(sl_int)  },
+  { RS(TIC_SUM_DELTA_IDLE),      QS(sl_int),   TS(sl_int)  },
+  { RS(TIC_SUM_DELTA_BUSY),      QS(sl_int),   TS(sl_int)  },
+  { RS(TIC_SUM_DELTA_TOTAL),     QS(sl_int),   TS(sl_int)  },
 
   { RS(SYS_CTX_SWITCHES),        QS(ul_int),   TS(ul_int)  },
   { RS(SYS_INTERRUPTS),          QS(ul_int),   TS(ul_int)  },
@@ -392,34 +392,33 @@ static inline void stat_assign_results (
 static inline void stat_derive_unique (
         struct hist_tic *this)
 {
-    /* note: we exclude guest tics from xtot since ...
-             'user' already includes 'guest'
-             'nice' already includes 'gnice'
-       ( see: ./kernel/sched/cputime.c, account_guest_time ) */
-    this->new.xtot
+    /* note: we calculate these derived values in a manner consistent with
+             the calculations for cgroup accounting, as nearly as possible
+       ( see linux sources: ./kernel/cgroup/rstat.c, root_cgroup_cputime ) */
+    this->new.xusr
         = this->new.user
-        + this->new.nice
-        + this->new.system
-        + this->new.idle
-        + this->new.iowait
+        + this->new.nice;
+    this->new.xsys
+        = this->new.system
         + this->new.irq
-        + this->new.sirq
-        + this->new.stolen;
-    this->new.xusr = this->new.user + this->new.nice;
-    /* this stolen guy is one i'm not sure of yet, but it's documented as:
-          "the time spent in other operating systems
-           when running in a virtualized environment"
-       so it would seem to apply to an 'involuntary wait' for a guest OS */
-    this->new.xidl = this->new.idle + this->new.iowait + this->new.stolen;
-    this->new.xbsy = this->new.xtot - this->new.xidl;
-    this->new.xsys = this->new.xbsy - this->new.xusr;
+        + this->new.sirq;
+    this->new.xidl
+        = this->new.idle
+        + this->new.iowait;
+    this->new.xtot
+        = this->new.xusr + this->new.xsys + this->new.xidl
+        + this->new.stolen
+        + this->new.guest
+        + this->new.gnice;
+    this->new.xbsy
+        = this->new.xtot - this->new.xidl;
 
     // don't distort deltas when cpus are taken offline or brought online
-    if (this->new.xtot < this->old.xtot
-    || (this->new.xusr < this->old.xusr)
+    if (this->new.xusr < this->old.xusr
+    || (this->new.xsys < this->old.xsys)
     || (this->new.xidl < this->old.xidl)
     || (this->new.xbsy < this->old.xbsy)
-    || (this->new.xsys < this->old.xsys))
+    || (this->new.xtot < this->old.xtot))
         memcpy(&this->old, &this->new, sizeof(struct stat_jifs));
 } // end: stat_derive_unique
 
@@ -526,11 +525,11 @@ static int stat_make_numa_hist (
             nod_ptr->new.guest  += cpu_ptr->new.guest;  nod_ptr->old.guest  += cpu_ptr->old.guest;
             nod_ptr->new.gnice  += cpu_ptr->new.gnice;  nod_ptr->old.gnice  += cpu_ptr->old.gnice;
 
-            nod_ptr->new.xtot += cpu_ptr->new.xtot;  nod_ptr->old.xtot += cpu_ptr->old.xtot;
-            nod_ptr->new.xbsy += cpu_ptr->new.xbsy;  nod_ptr->old.xbsy += cpu_ptr->old.xbsy;
-            nod_ptr->new.xidl += cpu_ptr->new.xidl;  nod_ptr->old.xidl += cpu_ptr->old.xidl;
             nod_ptr->new.xusr += cpu_ptr->new.xusr;  nod_ptr->old.xusr += cpu_ptr->old.xusr;
             nod_ptr->new.xsys += cpu_ptr->new.xsys;  nod_ptr->old.xsys += cpu_ptr->old.xsys;
+            nod_ptr->new.xidl += cpu_ptr->new.xidl;  nod_ptr->old.xidl += cpu_ptr->old.xidl;
+            nod_ptr->new.xbsy += cpu_ptr->new.xbsy;  nod_ptr->old.xbsy += cpu_ptr->old.xbsy;
+            nod_ptr->new.xtot += cpu_ptr->new.xtot;  nod_ptr->old.xtot += cpu_ptr->old.xtot;
 
             cpu_ptr->numa_node = nod_ptr->numa_node = node;
             nod_ptr->count++; ;

diff --git a/proc/stat.h b/proc/stat.h
index d4c75534001a4b5eba712ba659d672b80ee68615..9d0f30342714276cd68f49f3b288624038fe0835 100644 (file)
--- a/proc/stat.h
+++ b/proc/stat.h
@@ -54,17 +54,17 @@ enum stat_item {
     STAT_TIC_DELTA_GUEST,         //   sl_int         "
     STAT_TIC_DELTA_GUEST_NICE,    //   sl_int         "
 
-    STAT_TIC_SUM_TOTAL,           //  ull_int        derived from all except GUEST tics
-    STAT_TIC_SUM_IDLE,            //  ull_int        derived from IDLE + IOWAIT + STOLEN tics
     STAT_TIC_SUM_USER,            //  ull_int        derived from USER + NICE tics
+    STAT_TIC_SUM_SYSTEM,          //  ull_int        derived from SYSTEM + IRQ + SOFTIRQ tics
+    STAT_TIC_SUM_IDLE,            //  ull_int        derived from IDLE + IOWAIT tics
     STAT_TIC_SUM_BUSY,            //  ull_int        derived from SUM_TOTAL - SUM_IDLE tics
-    STAT_TIC_SUM_SYSTEM,          //  ull_int        derived from SUM_BUSY - SUM_USER tics
+    STAT_TIC_SUM_TOTAL,           //  ull_int        derived from sum of all 10 tics
 
-    STAT_TIC_SUM_DELTA_TOTAL,     //   sl_int        derived from above
+    STAT_TIC_SUM_DELTA_USER,      //   sl_int        derived from above
+    STAT_TIC_SUM_DELTA_SYSTEM,    //   sl_int         "
     STAT_TIC_SUM_DELTA_IDLE,      //   sl_int         "
-    STAT_TIC_SUM_DELTA_USER,      //   sl_int         "
     STAT_TIC_SUM_DELTA_BUSY,      //   sl_int         "
-    STAT_TIC_SUM_DELTA_SYSTEM,    //   sl_int         "
+    STAT_TIC_SUM_DELTA_TOTAL,     //   sl_int         "
 
     STAT_SYS_CTX_SWITCHES,        //   ul_int        /proc/stat
     STAT_SYS_INTERRUPTS,          //   ul_int         "