perf kvm can be used to analyze guest exit reasons. This support already
exists in x86. Hence, porting it to powerpc.
- To trace KVM events :
perf kvm stat record
If many guests are running, we can track for a specific guest by using
--pid as in : perf kvm stat record --pid <pid>
- To see the results :
perf kvm stat report
The result shows the number of exits (from the guest context to
host/hypervisor context) grouped by their respective exit reasons with
their frequency.
Since, different powerpc machines have different KVM tracepoints, this
patch discovers the machine type dynamically from /proc/cpuinfo's
"machine" tag and accordingly sets kvm tracepoints. Right now, it only
supports Book3S_HV tracepoints.
To analyze the different exits, group them and present them (in a slight
descriptive way) to the user, we need a mapping between the "exit
code" (dumped in the kvm_guest_exit tracepoint data) and to its related
Interrupt vector description (exit reason). This patch adds this mapping
in book3s_hv_exits.h.
It records on two available KVM tracepoints :
"kvm_hv:kvm_guest_exit" and "kvm_hv:kvm_guest_enter" exported through
arch/powerpc/include/uapi/asm/kvm_perf.h.
Here is a sample o/p:
# pgrep qemu
19378
60515
2 Guests are running on the host.
# perf kvm stat record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data.guest (39624
samples) ]
# perf kvm stat report -p 60515
Analyze events for pid(s) 60515, all VCPUs:
VM-EXIT Samples Samples% Time% Min Time Max Time
Avg time
SYSCALL 9141 63.67% 7.49% 1.26us 5782.39us
9.87us ( +- 6.46% )
H_DATA_STORAGE 4114 28.66% 5.07% 1.72us 4597.68us
14.84us ( +- 20.06% )
HV_DECREMENTER 418 2.91% 4.26% 0.70us 30002.22us
122.58us ( +- 70.29% )
EXTERNAL 392 2.73% 0.06% 0.64us 104.10us
1.94us ( +- 18.83% )
RETURN_TO_HOST 287 2.00% 83.11% 1.53us 124240.15us
3486.52us ( +- 16.81% )
H_INST_STORAGE 5 0.03% 0.00% 1.88us 3.73us
2.39us ( +- 14.20% )
Total Samples:14357, Total events handled time:1203918.42us.
Signed-off-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
Signed-off-by: Hemant Kumar <hem...@linux.vnet.ibm.com>
---
This patch has a direct dependency on :
http://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg93620.html
Changes since v5 :
- Added a dynamic discovery check for machine type.
- Made the kvm tracepoints recording/reporting conditional on machine type.
(Suggested by Scott Wood)
tools/perf/arch/powerpc/Makefile | 2 +
tools/perf/arch/powerpc/util/Build | 1 +
tools/perf/arch/powerpc/util/book3s_hv_exits.h | 33 ++++++
tools/perf/arch/powerpc/util/kvm-stat.c | 151 +++++++++++++++++++++++++
tools/perf/builtin-kvm.c | 16 ++-
tools/perf/util/kvm-stat.h | 1 +
6 files changed, 201 insertions(+), 3 deletions(-)
create mode 100644 tools/perf/arch/powerpc/util/book3s_hv_exits.h
create mode 100644 tools/perf/arch/powerpc/util/kvm-stat.c
diff --git a/tools/perf/arch/powerpc/Makefile b/tools/perf/arch/powerpc/Makefile
index 7fbca17..9f9cea3 100644
--- a/tools/perf/arch/powerpc/Makefile
+++ b/tools/perf/arch/powerpc/Makefile
@@ -1,3 +1,5 @@
ifndef NO_DWARF
PERF_HAVE_DWARF_REGS := 1
endif
+
+HAVE_KVM_STAT_SUPPORT := 1
diff --git a/tools/perf/arch/powerpc/util/Build
b/tools/perf/arch/powerpc/util/Build
index 7b8b0d1..c8fe207 100644
--- a/tools/perf/arch/powerpc/util/Build
+++ b/tools/perf/arch/powerpc/util/Build
@@ -1,5 +1,6 @@
libperf-y += header.o
libperf-y += sym-handling.o
+libperf-y += kvm-stat.o
libperf-$(CONFIG_DWARF) += dwarf-regs.o
libperf-$(CONFIG_DWARF) += skip-callchain-idx.o
diff --git a/tools/perf/arch/powerpc/util/book3s_hv_exits.h
b/tools/perf/arch/powerpc/util/book3s_hv_exits.h
new file mode 100644
index 0000000..e68ba2d
--- /dev/null
+++ b/tools/perf/arch/powerpc/util/book3s_hv_exits.h
@@ -0,0 +1,33 @@
+#ifndef ARCH_PERF_BOOK3S_HV_EXITS_H
+#define ARCH_PERF_BOOK3S_HV_EXITS_H
+
+/*
+ * PowerPC Interrupt vectors : exit code to name mapping
+ */
+
+#define kvm_trace_symbol_exit \
+ {0x0, "RETURN_TO_HOST"}, \
+ {0x100, "SYSTEM_RESET"}, \
+ {0x200, "MACHINE_CHECK"}, \
+ {0x300, "DATA_STORAGE"}, \
+ {0x380, "DATA_SEGMENT"}, \
+ {0x400, "INST_STORAGE"}, \
+ {0x480, "INST_SEGMENT"}, \
+ {0x500, "EXTERNAL"}, \
+ {0x501, "EXTERNAL_LEVEL"}, \
+ {0x502, "EXTERNAL_HV"}, \
+ {0x600, "ALIGNMENT"}, \
+ {0x700, "PROGRAM"}, \
+ {0x800, "FP_UNAVAIL"}, \
+ {0x900, "DECREMENTER"}, \
+ {0x980, "HV_DECREMENTER"}, \
+ {0xc00, "SYSCALL"}, \
+ {0xd00, "TRACE"}, \
+ {0xe00, "H_DATA_STORAGE"}, \
+ {0xe20, "H_INST_STORAGE"}, \
+ {0xe40, "H_EMUL_ASSIST"}, \
+ {0xf00, "PERFMON"}, \
+ {0xf20, "ALTIVEC"}, \
+ {0xf40, "VSX"}
+
+#endif
diff --git a/tools/perf/arch/powerpc/util/kvm-stat.c
b/tools/perf/arch/powerpc/util/kvm-stat.c
new file mode 100644
index 0000000..448bc51
--- /dev/null
+++ b/tools/perf/arch/powerpc/util/kvm-stat.c
@@ -0,0 +1,151 @@
+#include "../../util/kvm-stat.h"
+#include "book3s_hv_exits.h"
+#include <asm/kvm_perf.h>
+
+#define PPC_HV "PowerNV"
+#define KEY "machine"
+#define VM_ENTRY 0
+#define VM_EXIT 1
+#define NR_TPS 2
+
+/* Currently only supported on Book3S_HV machines */
+enum {
+ UNSUPPORTED = -1,
+ BOOK3S_HV = 0,
+} ppc_machine;
+
+define_exit_reasons_table(hv_exit_reasons, kvm_trace_symbol_exit);
+
+int ppc_type = UNSUPPORTED;
+const char *exit_reason;
+
+static struct kvm_events_ops exit_events = {
+ .is_begin_event = exit_event_begin,
+ .is_end_event = exit_event_end,
+ .decode_key = exit_event_decode_key,
+ .name = "VM-EXIT"
+};
+
+/* 1 extra placeholder for NULL */
+const char *kvm_events_tp[NR_TPS + 1];
+
+struct kvm_reg_events_ops kvm_reg_events_ops[] = {
+ { .name = "vmexit", .ops = &exit_events },
+ { NULL, NULL },
+};
+
+const char * const kvm_skip_events[] = {
+ NULL,
+};
+
+bool kvm_exit_event(struct perf_evsel *evsel)
+{
+ return !strncmp(evsel->name, kvm_events_tp[VM_EXIT],
+ strlen(kvm_events_tp[VM_EXIT]));
+}
+
+bool kvm_entry_event(struct perf_evsel *evsel)
+{
+ return !strncmp(evsel->name, kvm_events_tp[VM_ENTRY],
+ strlen(kvm_events_tp[VM_ENTRY]));
+}
+
+void exit_event_get_key(struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct event_key *key)
+{
+ key->info = 0;
+ key->key = perf_evsel__intval(evsel, sample, exit_reason);
+}
+
+/*
+ * Read the /proc/cpuinfo and find out the machine type
+ */
+static int find_ppc_type(void)
+{
+ FILE *file;
+ char *s, *p, *buf = NULL;
+ size_t len;
+ int ret = UNSUPPORTED;
+
+ file = fopen("/proc/cpuinfo", "r");
+ if (!file)
+ return -1;
+
+ while (getline(&buf, &len, file) > 0) {
+ ret = strncmp(buf, KEY, strlen(KEY));
+ if (!ret)
+ break;
+ }
+
+ if (ret) {
+ ret = -1;
+ goto done;
+ }
+
+ s = buf;
+ p = strchr(buf, ':');
+ if (p && *(p + 1) == ' ' && *(p + 2))
+ s = p + 2;
+
+ p = strchr(s, '\n');
+ if (p)
+ *p = '\0';
+
+ /* s has the machine type now */
+ if (!strncmp(s, PPC_HV, strlen(PPC_HV))) {
+ ret = BOOK3S_HV;
+ ppc_type = ret;
+ }
+
+done:
+ free(buf);
+ fclose(file);
+ return ret;
+}
+
+/*
+ * Depending on the machine type, setup the KVM tracepoints
+ */
+static int setup_kvm_tp(void)
+{
+ int ret;
+
+ ret = find_ppc_type();
+ switch (ret) {
+ case BOOK3S_HV:
+ /* Tracepoints related to Book3S_HV machines */
+ kvm_events_tp[VM_ENTRY] = KVM_ENTRY_TRACE_HV;
+ kvm_events_tp[VM_EXIT] = KVM_EXIT_TRACE_HV;
+ kvm_events_tp[NR_TPS] = NULL;
+ exit_reason = KVM_EXIT_REASON_HV;
+ break;
+ default:
+ kvm_events_tp[0] = NULL;
+ ret = UNSUPPORTED;
+ exit_reason = NULL;
+ }
+ return ret;
+}
+
+int setup_kvm_events_tp(void)
+{
+ return setup_kvm_tp();
+}
+
+int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid __maybe_unused)
+{
+ int ret = 0;
+
+ ret = setup_kvm_tp();
+ if (ret == BOOK3S_HV) {
+ kvm->exit_reasons = hv_exit_reasons;
+ kvm->exit_reasons_isa = "HV";
+ ret = 0;
+ } else {
+ kvm->exit_reasons = NULL;
+ kvm->exit_reasons_isa = NULL;
+ }
+
+ return ret;
+}
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index fc1cffb..87db36a 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -34,7 +34,7 @@
#include <asm/kvm_perf.h>
#include "util/kvm-stat.h"
-void exit_event_get_key(struct perf_evsel *evsel,
+void __weak exit_event_get_key(struct perf_evsel *evsel,
struct perf_sample *sample,
struct event_key *key)
{
@@ -42,7 +42,7 @@ void exit_event_get_key(struct perf_evsel *evsel,
key->key = perf_evsel__intval(evsel, sample, KVM_EXIT_REASON);
}
-bool kvm_exit_event(struct perf_evsel *evsel)
+bool __weak kvm_exit_event(struct perf_evsel *evsel)
{
return !strcmp(evsel->name, KVM_EXIT_TRACE);
}
@@ -58,7 +58,7 @@ bool exit_event_begin(struct perf_evsel *evsel,
return false;
}
-bool kvm_entry_event(struct perf_evsel *evsel)
+bool __weak kvm_entry_event(struct perf_evsel *evsel)
{
return !strcmp(evsel->name, KVM_ENTRY_TRACE);
}
@@ -1125,6 +1125,11 @@ exit:
return ret;
}
+int __weak setup_kvm_events_tp(void)
+{
+ return 0;
+}
+
#define STRDUP_FAIL_EXIT(s) \
({ char *_p; \
_p = strdup(s); \
@@ -1149,7 +1154,12 @@ kvm_events_record(struct perf_kvm_stat *kvm, int argc,
const char **argv)
NULL
};
const char * const *events_tp;
+ int ret;
+
events_tp_size = 0;
+ ret = setup_kvm_events_tp();
+ if (ret < 0)
+ return -EINVAL;
for (events_tp = kvm_events_tp; *events_tp; events_tp++)
events_tp_size++;
diff --git a/tools/perf/util/kvm-stat.h b/tools/perf/util/kvm-stat.h
index 6384672..f8f778b 100644
--- a/tools/perf/util/kvm-stat.h
+++ b/tools/perf/util/kvm-stat.h
@@ -136,5 +136,6 @@ int cpu_isa_init(struct perf_kvm_stat *kvm, const char
*cpuid);
extern const char *kvm_events_tp[];
extern struct kvm_reg_events_ops kvm_reg_events_ops[];
extern const char * const kvm_skip_events[];
+int setup_kvm_events_tp(void);
#endif /* __PERF_KVM_STAT_H */
--
1.9.3
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