[Xen-changelog] [xen-unstable] xen: tracing: introduce per-scheduler trace event IDs

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Dario Faggioli <dario.faggioli@xxxxxxxxxx>
# Date 1355854293 0
# Node ID c15b2aa0571faa564cd213f18f79de65166d1615
# Parent  5cc77f70f048d63990ef2827e0383b688ec08cc5
xen: tracing: introduce per-scheduler trace event IDs

So that it becomes possible to create scheduler specific trace
records, within each scheduler, without worrying about the
overlapping, and also without giving up being able to recognise them
univocally. The latter is deemed as useful, since we can have more
than one scheduler running at the same time, thanks to cpupools.

The event ID is 12 bits, and this change uses the upper 3 of them for
the 'scheduler ID'. This means we're limited to 8 schedulers and to
512 scheduler specific tracing events. Both seem reasonable
limitations as of now.

This also converts the existing credit2 tracing (the only scheduler
generating tracing events up to now) to the new system.

Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Committed-by: Keir Fraser <keir@xxxxxxx>
---


diff -r 5cc77f70f048 -r c15b2aa0571f xen/common/sched_credit2.c
--- a/xen/common/sched_credit2.c        Tue Dec 18 18:10:57 2012 +0000
+++ b/xen/common/sched_credit2.c        Tue Dec 18 18:11:33 2012 +0000
@@ -29,18 +29,22 @@
 #define d2printk(x...)
 //#define d2printk printk
 
-#define TRC_CSCHED2_TICK        TRC_SCHED_CLASS + 1
-#define TRC_CSCHED2_RUNQ_POS    TRC_SCHED_CLASS + 2
-#define TRC_CSCHED2_CREDIT_BURN TRC_SCHED_CLASS + 3
-#define TRC_CSCHED2_CREDIT_ADD  TRC_SCHED_CLASS + 4
-#define TRC_CSCHED2_TICKLE_CHECK TRC_SCHED_CLASS + 5
-#define TRC_CSCHED2_TICKLE       TRC_SCHED_CLASS + 6
-#define TRC_CSCHED2_CREDIT_RESET TRC_SCHED_CLASS + 7
-#define TRC_CSCHED2_SCHED_TASKLET TRC_SCHED_CLASS + 8
-#define TRC_CSCHED2_UPDATE_LOAD   TRC_SCHED_CLASS + 9
-#define TRC_CSCHED2_RUNQ_ASSIGN   TRC_SCHED_CLASS + 10
-#define TRC_CSCHED2_UPDATE_VCPU_LOAD   TRC_SCHED_CLASS + 11
-#define TRC_CSCHED2_UPDATE_RUNQ_LOAD   TRC_SCHED_CLASS + 12
+/*
+ * Credit2 tracing events ("only" 512 available!). Check
+ * include/public/trace.h for more details.
+ */
+#define TRC_CSCHED2_TICK             TRC_SCHED_CLASS_EVT(CSCHED2, 1)
+#define TRC_CSCHED2_RUNQ_POS         TRC_SCHED_CLASS_EVT(CSCHED2, 2)
+#define TRC_CSCHED2_CREDIT_BURN      TRC_SCHED_CLASS_EVT(CSCHED2, 3)
+#define TRC_CSCHED2_CREDIT_ADD       TRC_SCHED_CLASS_EVT(CSCHED2, 4)
+#define TRC_CSCHED2_TICKLE_CHECK     TRC_SCHED_CLASS_EVT(CSCHED2, 5)
+#define TRC_CSCHED2_TICKLE           TRC_SCHED_CLASS_EVT(CSCHED2, 6)
+#define TRC_CSCHED2_CREDIT_RESET     TRC_SCHED_CLASS_EVT(CSCHED2, 7)
+#define TRC_CSCHED2_SCHED_TASKLET    TRC_SCHED_CLASS_EVT(CSCHED2, 8)
+#define TRC_CSCHED2_UPDATE_LOAD      TRC_SCHED_CLASS_EVT(CSCHED2, 9)
+#define TRC_CSCHED2_RUNQ_ASSIGN      TRC_SCHED_CLASS_EVT(CSCHED2, 10)
+#define TRC_CSCHED2_UPDATE_VCPU_LOAD TRC_SCHED_CLASS_EVT(CSCHED2, 11)
+#define TRC_CSCHED2_UPDATE_RUNQ_LOAD TRC_SCHED_CLASS_EVT(CSCHED2, 12)
 
 /*
  * WARNING: This is still in an experimental phase.  Status and work can be 
found at the
diff -r 5cc77f70f048 -r c15b2aa0571f xen/include/public/trace.h
--- a/xen/include/public/trace.h        Tue Dec 18 18:10:57 2012 +0000
+++ b/xen/include/public/trace.h        Tue Dec 18 18:11:33 2012 +0000
@@ -57,6 +57,32 @@
 #define TRC_SCHED_CLASS     0x00022000   /* Scheduler-specific    */
 #define TRC_SCHED_VERBOSE   0x00028000   /* More inclusive scheduling */
 
+/*
+ * The highest 3 bits of the last 12 bits of TRC_SCHED_CLASS above are
+ * reserved for encoding what scheduler produced the information. The
+ * actual event is encoded in the last 9 bits.
+ *
+ * This means we have 8 scheduling IDs available (which means at most 8
+ * schedulers generating events) and, in each scheduler, up to 512
+ * different events.
+ */
+#define TRC_SCHED_ID_BITS 3
+#define TRC_SCHED_ID_SHIFT (TRC_SUBCLS_SHIFT - TRC_SCHED_ID_BITS)
+#define TRC_SCHED_ID_MASK (((1UL<<TRC_SCHED_ID_BITS) - 1) << 
TRC_SCHED_ID_SHIFT)
+#define TRC_SCHED_EVT_MASK (~(TRC_SCHED_ID_MASK))
+
+/* Per-scheduler IDs, to identify scheduler specific events */
+#define TRC_SCHED_CSCHED   0
+#define TRC_SCHED_CSCHED2  1
+#define TRC_SCHED_SEDF     2
+#define TRC_SCHED_ARINC653 3
+
+/* Per-scheduler tracing */
+#define TRC_SCHED_CLASS_EVT(_c, _e) \
+  ( ( TRC_SCHED_CLASS | \
+      ((TRC_SCHED_##_c << TRC_SCHED_ID_SHIFT) & TRC_SCHED_ID_MASK) ) + \
+    (_e & TRC_SCHED_EVT_MASK) )
+
 /* Trace classes for Hardware */
 #define TRC_HW_PM           0x00801000   /* Power management traces */
 #define TRC_HW_IRQ          0x00802000   /* Traces relating to the handling of 
IRQs */

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