[PATCH] powerpc: Instrument Hypervisor Calls
Mike Kravetz
kravetz at us.ibm.com
Thu Sep 7 09:23:12 EST 2006
Hi Paul,
This patch addresses the issues you brought up with the previous version.
The most important issue being range checking of opcodes so the code does
not write outside the array. You also suggested doing a load from TOC
instead of LOAD_REG_ADDR, because LOAD_REG_ADDR turns into 5 instructions.
I 'think' LOAD_REG_ADDR only turns into 5 instructions on 32 bit systems.
It is a single load from TOC on 64 bits as we are using it.
Here it is:
Add instrumentation for hypervisor calls on pseries. Call statistics
include number of calls, wall time and cpu cycles (if available) and
are made available via debugfs. Instrumentation code is behind the
HCALL_STATS config option and has no impact if not enabled.
--
Signed-off-by: Mike Kravetz <kravetz at us.ibm.com>
diff -Naupr powerpc/arch/powerpc/Kconfig.debug powerpc.work/arch/powerpc/Kconfig.debug
--- powerpc/arch/powerpc/Kconfig.debug 2006-09-06 22:40:53.000000000 +0000
+++ powerpc.work/arch/powerpc/Kconfig.debug 2006-09-06 23:41:40.000000000 +0000
@@ -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 callsr. Wall time spent in
+ each call is always calculated, and if available CPU cycles spent
+ are also calculated. 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 powerpc/arch/powerpc/kernel/asm-offsets.c powerpc.work/arch/powerpc/kernel/asm-offsets.c
--- powerpc/arch/powerpc/kernel/asm-offsets.c 2006-09-06 22:40:55.000000000 +0000
+++ powerpc.work/arch/powerpc/kernel/asm-offsets.c 2006-09-06 23:41:40.000000000 +0000
@@ -137,6 +137,7 @@ 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(SLBSHADOW_STACKVSID,
offsetof(struct slb_shadow, save_area[SLB_NUM_BOLTED - 1].vsid));
@@ -165,6 +166,12 @@ 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]));
diff -Naupr powerpc/arch/powerpc/platforms/pseries/Makefile powerpc.work/arch/powerpc/platforms/pseries/Makefile
--- powerpc/arch/powerpc/platforms/pseries/Makefile 2006-09-06 22:41:08.000000000 +0000
+++ powerpc.work/arch/powerpc/platforms/pseries/Makefile 2006-09-06 23:41:40.000000000 +0000
@@ -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
diff -Naupr powerpc/arch/powerpc/platforms/pseries/hvCall.S powerpc.work/arch/powerpc/platforms/pseries/hvCall.S
--- powerpc/arch/powerpc/platforms/pseries/hvCall.S 2006-09-06 22:41:08.000000000 +0000
+++ powerpc.work/arch/powerpc/platforms/pseries/hvCall.S 2006-09-06 23:41:40.000000000 +0000
@@ -10,9 +10,69 @@
#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 r0; /* get timebase and */ \
+ std r0,STK_PARM(r5)(r1); /* save for later */ \
+BEGIN_FTR_SECTION; \
+ mfspr r0,SPRN_PURR; /* get PURR and */ \
+ std r0,STK_PARM(r6)(r1); /* save for later */ \
+END_FTR_SECTION_IFCLR(CPU_FTR_PURR);
+
+/*
+ * postcall is performed immediately before function return which
+ * allows liberal use of volatile registers.
+ */
+#define HCALL_INST_POSTCALL \
+ ld r4,STK_PARM(r3)(r1); /* validate opcode */ \
+ cmpldi cr7,r4,MAX_HCALL_OPCODE; \
+ bgt- cr7,1f; \
+ \
+ /* get time and PURR snapshots after hcall */ \
+ mftb r7; /* timebase after */ \
+BEGIN_FTR_SECTION; \
+ mfspr r8,SPRN_PURR; /* PURR after */ \
+ ld r6,STK_PARM(r6)(r1); /* PURR before */ \
+ subf r6,r6,r8; /* delta */ \
+END_FTR_SECTION_IFCLR(CPU_FTR_PURR); \
+ ld r5,STK_PARM(r5)(r1); /* timebase before */ \
+ subf r5,r5,r7; /* time delta */ \
+ \
+ /* calculate address of stat structure r4 = opcode */ \
+ srdi r4,r4,2; /* 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); \
+BEGIN_FTR_SECTION; \
+ ld r7,HCALL_STAT_PURR(r4); /* PURR */ \
+ add r7,r7,r6; \
+ std r7,HCALL_STAT_PURR(r4); \
+END_FTR_SECTION_IFCLR(CPU_FTR_PURR); \
+1:
+#else
+#define HCALL_INST_PRECALL
+#define HCALL_INST_POSTCALL
+#endif
+
.text
_GLOBAL(plpar_hcall_norets)
@@ -21,8 +81,12 @@ _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 +97,8 @@ _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 +116,8 @@ _GLOBAL(plpar_hcall)
std r6, 16(r12)
std r7, 24(r12)
+ HCALL_INST_POSTCALL
+
lwz r0,8(r1)
mtcrf 0xff,r0
@@ -61,6 +129,8 @@ _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 +156,8 @@ _GLOBAL(plpar_hcall9)
std r11,56(r12)
std r12,64(r12)
+ HCALL_INST_POSTCALL
+
lwz r0,8(r1)
mtcrf 0xff,r0
diff -Naupr powerpc/arch/powerpc/platforms/pseries/hvCall_inst.c powerpc.work/arch/powerpc/platforms/pseries/hvCall_inst.c
--- powerpc/arch/powerpc/platforms/pseries/hvCall_inst.c 1970-01-01 00:00:00.000000000 +0000
+++ powerpc.work/arch/powerpc/platforms/pseries/hvCall_inst.c 2006-09-06 23:42:55.000000000 +0000
@@ -0,0 +1,129 @@
+/*
+ * 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>
+#include <asm/cputable.h>
+
+DEFINE_PER_CPU(struct hcall_stats[HCALL_STAT_ARRAY_SIZE], hcall_stats);
+
+/*
+ * Routines for displaying the statistics in debugfs
+ */
+static void *hc_start(struct seq_file *m, loff_t *pos)
+{
+ if ((int)*pos < HCALL_STAT_ARRAY_SIZE)
+ 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) {
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ 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);
+ else
+ seq_printf(m, "%lu %lu %lu\n", h_num<<2,
+ hs[h_num].num_calls,
+ hs[h_num].tb_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);
diff -Naupr powerpc/include/asm-powerpc/hvcall.h powerpc.work/include/asm-powerpc/hvcall.h
--- powerpc/include/asm-powerpc/hvcall.h 2006-09-06 22:45:48.000000000 +0000
+++ powerpc.work/include/asm-powerpc/hvcall.h 2006-09-06 23:42:16.000000000 +0000
@@ -208,7 +208,7 @@
#define H_JOIN 0x298
#define H_VASI_STATE 0x2A4
#define H_ENABLE_CRQ 0x2B0
-#define MAX_HCALL_OPCODES (H_ENABLE_CRQ >> 2)
+#define MAX_HCALL_OPCODE H_ENABLE_CRQ
#ifndef __ASSEMBLY__
@@ -246,6 +246,16 @@ 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);
+#define HCALL_STAT_ARRAY_SIZE ((MAX_HCALL_OPCODE >> 2) + 1)
+
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_HVCALL_H */
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