[PATCH] powerpc: Instrument Hypervisor Calls

@@ -18,6 +18,20 @@ 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: both wall time (based
+	  on time base) and cpu time (based on PURR).  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

@@ -136,6 +136,7 @@ int main(void)
 	DEFINE(PACA_USER_TIME, offsetof(struct paca_struct, user_time));
 	DEFINE(PACA_SYSTEM_TIME, offsetof(struct paca_struct, system_time));
 	DEFINE(PACA_SLBSHADOWPTR, offsetof(struct paca_struct, slb_shadow_ptr));
+	DEFINE(PACA_DATA_OFFSET, offsetof(struct paca_struct, data_offset));
 
 	DEFINE(LPPACASRR0, offsetof(struct lppaca, saved_srr0));
 	DEFINE(LPPACASRR1, offsetof(struct lppaca, saved_srr1));

@@ -160,6 +161,12 @@ int main(void)
 	/* Create extra stack space for SRR0 and SRR1 when calling prom/rtas. */
 	DEFINE(PROM_FRAME_SIZE, STACK_FRAME_OVERHEAD + sizeof(struct pt_regs) + 16);
 	DEFINE(RTAS_FRAME_SIZE, STACK_FRAME_OVERHEAD + sizeof(struct pt_regs) + 16);
+
+	/* hcall statistics */
+	DEFINE(HCALL_STAT_SIZE, sizeof(struct hcall_stats));
+	DEFINE(HCALL_STAT_CALLS, offsetof(struct hcall_stats, num_calls));
+	DEFINE(HCALL_STAT_TB, offsetof(struct hcall_stats, tb_total));
+	DEFINE(HCALL_STAT_PURR, offsetof(struct hcall_stats, purr_total));
 #endif /* CONFIG_PPC64 */
 	DEFINE(GPR0, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[0]));
 	DEFINE(GPR1, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[1]));

@@ -12,3 +12,4 @@ 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

@@ -10,9 +10,66 @@
 #include <asm/hvcall.h>
 #include <asm/processor.h>
 #include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
 	
 #define STK_PARM(i)     (48 + ((i)-3)*8)
 
+#ifdef CONFIG_HCALL_STATS
+/*
+ * precall must preserve all registers.  use unused STK_PARM()
+ * areas to save snapshots and opcode.
+ */
+#define HCALL_INST_PRECALL					\
+	std	r3,STK_PARM(r3)(r1);	/* save opcode */	\
+	mftb	r3;			/* get timebase and */	\
+	std     r3,STK_PARM(r5)(r1);	/* save for later */	\
+BEGIN_FTR_SECTION;						\
+	mfspr	r3,SPRN_PURR;		/* get PURR and */	\
+END_FTR_SECTION_IFSET(CPU_FTR_PURR);				\
+	std	r3,STK_PARM(r6)(r1);	/* save for later */	\
+	ld	r3,STK_PARM(r3)(r1);	/* opcode back in r3 */
+	
+/*
+ * postcall is performed immediately before function return which
+ * allows liberal use of volital registers.
+ */
+#define HCALL_INST_POSTCALL					\
+	/* get time and PURR snapshots after hcall */		\
+	mftb	r7;			/* timebase after */	\
+BEGIN_FTR_SECTION;						\
+	mfspr	r8,SPRN_PURR;		/* PURR after */	\
+END_FTR_SECTION_IFSET(CPU_FTR_PURR);				\
+								\
+	/* calculate time and PURR deltas for call */		\
+	ld	r5,STK_PARM(r5)(r1);	/* timebase before */	\
+	subf	r5,r5,r7;					\
+	ld	r6,STK_PARM(r6)(r1);	/* PURR before */	\
+	subf	r6,r6,r8;					\
+								\
+	/* calculate address of stat structure */		\
+	ld	r4,STK_PARM(r3)(r1);	/* use opcode as */	\
+	rldicl	r4,r4,62,2;		/* index into array */	\
+	mulli	r4,r4,HCALL_STAT_SIZE;				\
+	LOAD_REG_ADDR(r7, per_cpu__hcall_stats);		\
+	add	r4,r4,r7;					\
+	ld	r7,PACA_DATA_OFFSET(r13); /* per cpu offset */	\
+	add	r4,r4,r7;					\
+								\
+	/* update stats	*/					\
+	ld	r7,HCALL_STAT_CALLS(r4); /* count */		\
+	addi	r7,r7,1;					\
+	std	r7,HCALL_STAT_CALLS(r4);			\
+	ld      r7,HCALL_STAT_TB(r4);	/* timebase */		\
+	add	r7,r7,r5;					\
+	std	r7,HCALL_STAT_TB(r4);				\
+	ld	r7,HCALL_STAT_PURR(r4);	/* PURR */		\
+	add	r7,r7,r6;					\
+	std	r7,HCALL_STAT_PURR(r4);
+#else
+#define HCALL_INST_PRECALL
+#define HCALL_INST_POSTCALL
+#endif
+
 	.text
 
 _GLOBAL(plpar_hcall_norets)

@@ -21,8 +78,12 @@ _GLOBAL(plpar_hcall_norets)
 	mfcr	r0
 	stw	r0,8(r1)
 
+	HCALL_INST_PRECALL
+
 	HVSC				/* invoke the hypervisor */
 
+	HCALL_INST_POSTCALL
+
 	lwz	r0,8(r1)
 	mtcrf	0xff,r0
 	blr				/* return r3 = status */

@@ -33,6 +94,8 @@ _GLOBAL(plpar_hcall)
 	mfcr	r0
 	stw	r0,8(r1)
 
+	HCALL_INST_PRECALL
+
 	std     r4,STK_PARM(r4)(r1)     /* Save ret buffer */
 
 	mr	r4,r5

@@ -50,6 +113,8 @@ _GLOBAL(plpar_hcall)
 	std	r6, 16(r12)
 	std	r7, 24(r12)
 
+	HCALL_INST_POSTCALL
+
 	lwz	r0,8(r1)
 	mtcrf	0xff,r0
 

@@ -61,6 +126,8 @@ _GLOBAL(plpar_hcall9)
 	mfcr	r0
 	stw	r0,8(r1)
 
+	HCALL_INST_PRECALL
+
 	std     r4,STK_PARM(r4)(r1)     /* Save ret buffer */
 
 	mr	r4,r5

@@ -86,6 +153,8 @@ _GLOBAL(plpar_hcall9)
 	std	r11,56(r12)
 	std	r12,64(r12)
 
+	HCALL_INST_POSTCALL
+
 	lwz	r0,8(r1)
 	mtcrf	0xff,r0
 

@@ -0,0 +1,122 @@
+/*
+ * 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);
+
+/*
+ * Routines for displaying the statistics in debugfs
+ */
+static void *hc_start(struct seq_file *m, loff_t *pos)
+{
+	if ((int)*pos < (MAX_HCALL_OPCODES + 1))
+		return (void *)(unsigned long)(*pos + 1);
+
+	return NULL;
+}
+
+static void *hc_next(struct seq_file *m, void *p, loff_t * pos)
+{
+	++*pos;
+
+	return hc_start(m, pos);
+}
+
+static void hc_stop(struct seq_file *m, void *p)
+{
+}
+
+static int hc_show(struct seq_file *m, void *p)
+{
+	unsigned long h_num = (unsigned long)p;
+	struct hcall_stats *hs = (struct hcall_stats *)m->private;
+
+	if (hs[h_num].num_calls)
+		seq_printf(m, "%lu %lu %lu %lu\n", h_num<<2,
+			   hs[h_num].num_calls,
+			   hs[h_num].tb_total,
+			   hs[h_num].purr_total);
+
+	return 0;
+}
+
+static struct seq_operations hcall_inst_seq_ops = {
+        .start = hc_start,
+        .next  = hc_next,
+        .stop  = hc_stop,
+        .show  = hc_show
+};
+
+static int hcall_inst_seq_open(struct inode *inode, struct file *file)
+{
+	int rc;
+	struct seq_file *seq;
+
+	rc = seq_open(file, &hcall_inst_seq_ops);
+	seq = file->private_data;
+	seq->private = file->f_dentry->d_inode->u.generic_ip;
+
+	return rc;
+}
+
+static struct file_operations hcall_inst_seq_fops = {
+	.open = hcall_inst_seq_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+#define	HCALL_ROOT_DIR		"hcall_inst"
+#define CPU_NAME_BUF_SIZE	32
+
+static int __init hcall_inst_init(void)
+{
+	struct dentry *hcall_root;
+	struct dentry *hcall_file;
+	char cpu_name_buf[CPU_NAME_BUF_SIZE];
+	int cpu;
+
+	if (!firmware_has_feature(FW_FEATURE_LPAR))
+		return 0;
+
+	hcall_root = debugfs_create_dir(HCALL_ROOT_DIR, NULL);
+	if (!hcall_root)
+		return -ENOMEM;
+
+	for_each_possible_cpu(cpu) {
+		snprintf(cpu_name_buf, CPU_NAME_BUF_SIZE, "cpu%d", cpu);
+		hcall_file = debugfs_create_file(cpu_name_buf, S_IRUGO,
+						 hcall_root,
+						 per_cpu(hcall_stats, cpu),
+						 &hcall_inst_seq_fops);
+		if (!hcall_file)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+__initcall(hcall_inst_init);

@@ -246,6 +246,15 @@ long plpar_hcall(unsigned long opcode, u
 #define PLPAR_HCALL9_BUFSIZE 9
 long plpar_hcall9(unsigned long opcode, unsigned long *retbuf, ...);
 
+/* For hcall instrumentation.  One structure per-hcall, per-CPU */
+struct hcall_stats {
+	unsigned long	num_calls;	/* number of calls (on this CPU) */
+	unsigned long	tb_total;	/* total wall time (mftb) of calls. */
+	unsigned long	purr_total;	/* total cpu time (PURR) of calls. */
+};
+void update_hcall_stats(unsigned long opcode, unsigned long tb_delta,
+			unsigned long purr_delta);
+
 #endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_HVCALL_H */