Subject: [PATCH 2/3] powerpc: Instrument Hypervisor Calls: add wrappers

From: Mike Kravetz <[email-masked]>
Date: Fri, 14 Jul 2006 16:40:34 -0700

Add wrappers which perform the actual hypervisor call instrumentation.
--
Signed-off-by: Mike Kravetz <[email-masked]>

diff -Naupr linux-2.6.17.4/arch/powerpc/Kconfig.debug linux-2.6.17.4.work/arch/powerpc/Kconfig.debug
--- linux-2.6.17.4/arch/powerpc/Kconfig.debug	2006-07-06 20:02:28.000000000 +0000
+++ linux-2.6.17.4.work/arch/powerpc/Kconfig.debug	2006-07-14 23:28:20.000000000 +0000
@@ -18,6 +18,19 @@ config DEBUG_STACK_USAGE
 
 	  This option will slow down process creation somewhat.
 
+config HCALL_STATS
+	bool "Hypervisor call instrumentation"
+	depends on PPC_PSERIES && DEBUG_FS
+	help
+	  Adds code to keep track of the number of hypervisor calls made and
+	  the amount of time spent in hypervisor calls.  A directory named
+	  hcall_inst is added at the root of the debugfs filesystem.  Within
+	  the hcall_inst directory are files that contain CPU specific call
+	  statistics.
+
+	  This option will add a small amount of overhead to all hypervisor
+	  calls.
+
 config DEBUGGER
 	bool "Enable debugger hooks"
 	depends on DEBUG_KERNEL
diff -Naupr linux-2.6.17.4/arch/powerpc/platforms/pseries/Makefile linux-2.6.17.4.work/arch/powerpc/platforms/pseries/Makefile
--- linux-2.6.17.4/arch/powerpc/platforms/pseries/Makefile	2006-07-06 20:02:28.000000000 +0000
+++ linux-2.6.17.4.work/arch/powerpc/platforms/pseries/Makefile	2006-07-14 23:28:20.000000000 +0000
@@ -9,3 +9,4 @@ obj-$(CONFIG_EEH)	+= eeh.o eeh_cache.o e
 
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
+obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
diff -Naupr linux-2.6.17.4/arch/powerpc/platforms/pseries/hvCall.S linux-2.6.17.4.work/arch/powerpc/platforms/pseries/hvCall.S
--- linux-2.6.17.4/arch/powerpc/platforms/pseries/hvCall.S	2006-07-06 20:02:28.000000000 +0000
+++ linux-2.6.17.4.work/arch/powerpc/platforms/pseries/hvCall.S	2006-07-14 23:28:20.000000000 +0000
@@ -11,7 +11,35 @@
 #include <asm/hvcall.h>
 #include <asm/processor.h>
 #include <asm/ppc_asm.h>
-	
+
+/*
+ * If hcall statistics are desired, all routines are wrapped with code
+ * that does the statistic gathering.
+ */
+#ifndef CONFIG_HCALL_STATS
+#define PLPAR_HCALL		plpar_hcall
+#define PLPAR_HCALL_NORETS	plpar_hcall_norets
+#define PLPAR_HCALL_8ARG_2RET	plpar_hcall_8arg_2ret
+#define PLPAR_HCALL_4OUT	plpar_hcall_4out
+#define PLPAR_HCALL_7ARG_7RET	plpar_hcall_7arg_7ret
+#define PLPAR_HCALL_9ARG_9RET	plpar_hcall_9arg_9ret
+#else
+#define PLPAR_HCALL		plpar_hcall_base
+#define PLPAR_HCALL_NORETS	plpar_hcall_norets_base
+#define PLPAR_HCALL_8ARG_2RET	plpar_hcall_8arg_2ret_base
+#define PLPAR_HCALL_4OUT	plpar_hcall_4out_base
+#define PLPAR_HCALL_7ARG_7RET	plpar_hcall_7arg_7ret_base
+#define PLPAR_HCALL_9ARG_9RET	plpar_hcall_9arg_9ret_base
+
+/*
+ * A special 'indirect' call to a C based wrapper if statistics are desired.
+ * See plpar_hcall_norets_C function header for more details.
+ */
+_GLOBAL(plpar_hcall_norets)
+	b	plpar_hcall_norets_C
+
+#endif
+
 #define STK_PARM(i)     (48 + ((i)-3)*8)
 
 	.text
@@ -25,7 +53,7 @@
 			unsigned long *out2,		R9
 			unsigned long *out3);		R10
  */
-_GLOBAL(plpar_hcall)
+_GLOBAL(PLPAR_HCALL)
 	HMT_MEDIUM
 
 	mfcr	r0
@@ -52,7 +80,7 @@ _GLOBAL(plpar_hcall)

 /* Simple interface with no output values (other than status) */
-_GLOBAL(plpar_hcall_norets)
+_GLOBAL(PLPAR_HCALL_NORETS)
 	HMT_MEDIUM
 
 	mfcr	r0
@@ -76,7 +104,7 @@ _GLOBAL(plpar_hcall_norets)
 			unsigned long arg8,		112(R1)
 			unsigned long *out1);		120(R1)
  */
-_GLOBAL(plpar_hcall_8arg_2ret)
+_GLOBAL(PLPAR_HCALL_8ARG_2RET)
 	HMT_MEDIUM
 
 	mfcr	r0
@@ -102,7 +130,7 @@ _GLOBAL(plpar_hcall_8arg_2ret)
 		 	unsigned long *out3,		R10
 		 	unsigned long *out4);		112(R1)
  */
-_GLOBAL(plpar_hcall_4out)
+_GLOBAL(PLPAR_HCALL_4OUT)
 	HMT_MEDIUM
 
 	mfcr	r0
@@ -144,7 +172,7 @@ _GLOBAL(plpar_hcall_4out)
 			 unsigned long *out6,		102(R1)
 			 unsigned long *out7);		100(R1)
 */
-_GLOBAL(plpar_hcall_7arg_7ret)
+_GLOBAL(PLPAR_HCALL_7ARG_7RET)
 	HMT_MEDIUM
 
 	mfcr	r0
@@ -193,7 +221,7 @@ _GLOBAL(plpar_hcall_7arg_7ret)
 			 unsigned long *out8,		 94(R1)
 		         unsigned long *out9,            92(R1)
 */
-_GLOBAL(plpar_hcall_9arg_9ret)
+_GLOBAL(PLPAR_HCALL_9ARG_9RET)
 	HMT_MEDIUM
 
 	mfcr	r0
diff -Naupr linux-2.6.17.4/arch/powerpc/platforms/pseries/hvCall_inst.c linux-2.6.17.4.work/arch/powerpc/platforms/pseries/hvCall_inst.c
--- linux-2.6.17.4/arch/powerpc/platforms/pseries/hvCall_inst.c	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.17.4.work/arch/powerpc/platforms/pseries/hvCall_inst.c	2006-07-14 23:28:44.000000000 +0000
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2006 Mike Kravetz IBM Corporation
+ *
+ * Hypervisor Call Instrumentation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/percpu.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/cpumask.h>
+#include <asm/hvcall.h>
+#include <asm/firmware.h>
+
+DEFINE_PER_CPU(struct hcall_stats[MAX_HCALL_OPCODES+1], hcall_stats);
+
+/*
+ * Common update of the per-CPU/per-hcall statistics
+ */
+static inline void update_stats(unsigned long opcode, unsigned long t_before)
+{
+	unsigned long op_index = opcode >> 2;
+	struct hcall_stats *hs = &__get_cpu_var(hcall_stats[op_index]);
+
+	hs->total_time += (mftb() - t_before);
+	hs->num_calls++;
+}
+
+/*
+ * plpar_hcall wrapper
+ */
+long plpar_hcall(unsigned long opcode,
+                 unsigned long arg1,
+                 unsigned long arg2,
+                 unsigned long arg3,
+                 unsigned long arg4,
+                 unsigned long *out1,
+                 unsigned long *out2,
+                 unsigned long *out3)
+{
+	long rc;
+	unsigned long t_before;
+
+	t_before = mftb();
+	rc = plpar_hcall_base(opcode, arg1, arg2, arg3, arg4, out1, out2, out3);
+
+	update_stats(opcode, t_before);
+	return rc;
+}
+
+/*
+ * A C based wrapper for plpar_hcall_norets
+ * The wrapper for plpar_hcall_norets is a special case because the function
+ * takes a variable number of arguments.  It is almost impossible to write a
+ * wrapper for a function that takes a variable number of arguments in C.
+ * Therefore, there is an assembly routine in hvCall.S that simply branches
+ * to this C wrapper.  This 'indirection' takes care of the variable arguments
+ * issue.  This C wrapper has a fixed maximum number of arguments.
+ */
+long plpar_hcall_norets_C(unsigned long opcode,
+				unsigned long arg1,
+				unsigned long arg2,
+				unsigned long arg3,
+				unsigned long arg4,
+				unsigned long arg5,
+				unsigned long arg6)
+{
+	long rc;
+	unsigned long t_before;
+
+	t_before = mftb();
+	rc = plpar_hcall_norets_base(opcode, arg1, arg2, arg3, arg4, arg5,
+				     arg6);
+
+	update_stats(opcode, t_before);
+	return rc;
+}
+
+/*
+ * plpar_hcall_8arg_2ret wrapper
+ */
+long plpar_hcall_8arg_2ret(unsigned long opcode,
+                           unsigned long arg1,
+                           unsigned long arg2,
+                           unsigned long arg3,
+                           unsigned long arg4,
+                           unsigned long arg5,
+                           unsigned long arg6,
+                           unsigned long arg7,
+                           unsigned long arg8,
+                           unsigned long *out1)
+{
+	long rc;
+	unsigned long t_before;
+
+	t_before = mftb();
+	rc = plpar_hcall_8arg_2ret_base(opcode, arg1, arg2, arg3, arg4, arg5,
+					arg6, arg7, arg8, out1);
+
+	update_stats(opcode, t_before);
+	return rc;
+}
+
+/*
+ * plpar_hcall_4out wrapper
+ */
+long plpar_hcall_4out(unsigned long opcode,
+                      unsigned long arg1,
+                      unsigned long arg2,
+                      unsigned long arg3,
+                      unsigned long arg4,
+                      unsigned long *out1,
+                      unsigned long *out2,
+                      unsigned long *out3,
+                      unsigned long *out4)
+{
+	long rc;
+	unsigned long t_before;
+
+	t_before = mftb();
+	rc = plpar_hcall_4out_base(opcode, arg1, arg2, arg3, arg4, out1,
+				   out2, out3, out4);
+
+	update_stats(opcode, t_before);
+	return rc;
+}
+
+/*
+ * plpar_hcall_7arg_7ret wrapper
+ */
+long plpar_hcall_7arg_7ret(unsigned long opcode,
+                           unsigned long arg1,
+                           unsigned long arg2,
+                           unsigned long arg3,
+                           unsigned long arg4,
+                           unsigned long arg5,
+                           unsigned long arg6,
+                           unsigned long arg7,
+                           unsigned long *out1,
+                           unsigned long *out2,
+                           unsigned long *out3,
+                           unsigned long *out4,
+                           unsigned long *out5,
+                           unsigned long *out6,
+                           unsigned long *out7)
+{
+	long rc;
+	unsigned long t_before;
+
+	t_before = mftb();
+	rc = plpar_hcall_7arg_7ret_base(opcode, arg1, arg2, arg3, arg4, arg5,
+					arg6, arg7, out1, out2, out3, out4,
+					out5, out6, out7);
+
+	update_stats(opcode, t_before);
+	return rc;
+}
+
+/*
+ * plpar_hcall_9arg_9ret wrapper
+ */
+long plpar_hcall_9arg_9ret(unsigned long opcode,
+                           unsigned long arg1,
+                           unsigned long arg2,
+                           unsigned long arg3,
+                           unsigned long arg4,
+                           unsigned long arg5,
+                           unsigned long arg6,
+                           unsigned long arg7,
+                           unsigned long arg8,
+                           unsigned long arg9,
+                           unsigned long *out1,
+                           unsigned long *out2,
+                           unsigned long *out3,
+                           unsigned long *out4,
+                           unsigned long *out5,
+                           unsigned long *out6,
+                           unsigned long *out7,
+                           unsigned long *out8,
+                           unsigned long *out9)
+{
+	long rc;
+	unsigned long t_before;
+
+	t_before = mftb();
+	rc = plpar_hcall_9arg_9ret_base(opcode, arg1, arg2, arg3, arg4, arg5,
+					arg6, arg7, arg8, arg9, out1, out2,
+					out3, out4, out5, out6, out7, out8,
+					out9);
+
+	update_stats(opcode, t_before);
+	return rc;
+}
diff -Naupr linux-2.6.17.4/include/asm-powerpc/hvcall.h linux-2.6.17.4.work/include/asm-powerpc/hvcall.h
--- linux-2.6.17.4/include/asm-powerpc/hvcall.h	2006-07-14 23:27:52.000000000 +0000
+++ linux-2.6.17.4.work/include/asm-powerpc/hvcall.h	2006-07-14 23:28:20.000000000 +0000
@@ -292,6 +292,86 @@ long plpar_hcall_9arg_9ret(unsigned long
 			   unsigned long *out8,
 			   unsigned long *out9);
 
+
+/* For hcall instrumentation.  One structure per-hcall, per-CPU */
+struct hcall_stats {
+	unsigned long	num_calls;	/* number of calls (on this CPU) */
+	unsigned long	total_time;	/* total cputime (PURR) of calls. */
+};
+
+/* If Hypervisor call instrumentation is enabled, the assembly routine
+ * names are changed from 'plpar_hcall*' to 'plpar_hcall*_base' and
+ * 'plpar_hcall*' routines become instrumented wrappers.  The following
+ * are declarations for the renamed 'plpar_hcall*_base' routines.
+ */
+long plpar_hcall_base (unsigned long opcode,
+		       unsigned long arg1,
+		       unsigned long arg2,
+		       unsigned long arg3,
+		       unsigned long arg4,
+		       unsigned long *out1,
+		       unsigned long *out2,
+		       unsigned long *out3);
+
+long plpar_hcall_norets_base(unsigned long opcode, ...);
+
+long plpar_hcall_8arg_2ret_base(unsigned long opcode,
+				unsigned long arg1,
+				unsigned long arg2,
+				unsigned long arg3,
+				unsigned long arg4,
+				unsigned long arg5,
+				unsigned long arg6,
+				unsigned long arg7,
+				unsigned long arg8,
+				unsigned long *out1);
+
+long plpar_hcall_4out_base(unsigned long opcode,
+			   unsigned long arg1,
+			   unsigned long arg2,
+			   unsigned long arg3,
+			   unsigned long arg4,
+			   unsigned long *out1,
+			   unsigned long *out2,
+			   unsigned long *out3,
+			   unsigned long *out4);
+
+long plpar_hcall_7arg_7ret_base(unsigned long opcode,
+				unsigned long arg1,
+				unsigned long arg2,
+				unsigned long arg3,
+				unsigned long arg4,
+				unsigned long arg5,
+				unsigned long arg6,
+				unsigned long arg7,
+				unsigned long *out1,
+				unsigned long *out2,
+				unsigned long *out3,
+				unsigned long *out4,
+				unsigned long *out5,
+				unsigned long *out6,
+				unsigned long *out7);
+
+long plpar_hcall_9arg_9ret_base(unsigned long opcode,
+				unsigned long arg1,
+				unsigned long arg2,
+				unsigned long arg3,
+				unsigned long arg4,
+				unsigned long arg5,
+				unsigned long arg6,
+				unsigned long arg7,
+				unsigned long arg8,
+				unsigned long arg9,
+				unsigned long *out1,
+				unsigned long *out2,
+				unsigned long *out3,
+				unsigned long *out4,
+				unsigned long *out5,
+				unsigned long *out6,
+				unsigned long *out7,
+				unsigned long *out8,
+				unsigned long *out9);
+
 #endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_HVCALL_H */