Re: [PATCH v2] perf kvm: Add kvm-stat for loongarch64

From: Ian Rogers
Date: Sun Apr 07 2024 - 15:08:45 EST

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In reply to: Bibo Mao: "[PATCH v2] perf kvm: Add kvm-stat for loongarch64"
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On Sun, Apr 7, 2024 at 1:37 AM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
>
> Add support for 'perf kvm stat' on loongarch64 platform, now only
> kvm exit event is supported.
>
> Here is example output about "perf kvm --host stat report" command
>
> Event name Samples Sample% Time (ns) Time% Mean Time (ns)
> Mem store 83969 51.00% 625697070 8.00% 7451
> Mem read 37641 22.00% 112485730 1.00% 2988
> Interrupt 15542 9.00% 20620190 0.00% 1326
> Iocsr 15207 9.00% 94296190 1.00% 6200
> Hypercall 4873 2.00% 12265280 0.00% 2516
> Idle 3713 2.00% 6322055860 87.00% 1702681
> FPU 1819 1.00% 2750300 0.00% 1511
> Ifecth 502 0.00% 1341740 0.00% 2672
> Mem modify 324 0.00% 602240 0.00% 1858
> Cpucfg 55 0.00% 77610 0.00% 1411
> Csr 12 0.00% 19690 0.00% 1640
> LASX 3 0.00% 4870 0.00% 1623
> LSX 2 0.00% 2100 0.00% 1050
>
> Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> v1 --- v2:
> 1. Add child_ops for kvm exit event, split kvm:kvm_exit_gspr events
> into cpucfg/csr/iocsr/idle child events by decoding detailed gspr
> instruction.
> 2. Remove some exception code type which does not happen in current
> kvm implementation, such as meomry NR/NX/priviledge exception.
> ---
> tools/perf/arch/loongarch/Makefile | 1 +
> tools/perf/arch/loongarch/util/Build | 2 +
> tools/perf/arch/loongarch/util/header.c | 85 +++++++++++++
> tools/perf/arch/loongarch/util/kvm-stat.c | 141 ++++++++++++++++++++++
> 4 files changed, 229 insertions(+)
> create mode 100644 tools/perf/arch/loongarch/util/header.c
> create mode 100644 tools/perf/arch/loongarch/util/kvm-stat.c
>
> diff --git a/tools/perf/arch/loongarch/Makefile b/tools/perf/arch/loongarch/Makefile
> index 3992a67a87d9..c89d6bb6b184 100644
> --- a/tools/perf/arch/loongarch/Makefile
> +++ b/tools/perf/arch/loongarch/Makefile
> @@ -4,6 +4,7 @@ PERF_HAVE_DWARF_REGS := 1
> endif
> PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET := 1
> PERF_HAVE_JITDUMP := 1
> +HAVE_KVM_STAT_SUPPORT := 1
>
> #
> # Syscall table generation for perf
> diff --git a/tools/perf/arch/loongarch/util/Build b/tools/perf/arch/loongarch/util/Build
> index d776125a2d06..e1a13761037b 100644
> --- a/tools/perf/arch/loongarch/util/Build
> +++ b/tools/perf/arch/loongarch/util/Build
> @@ -1,5 +1,7 @@
> perf-y += perf_regs.o
> +perf-y += header.o
>
> +perf-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
> perf-$(CONFIG_DWARF) += dwarf-regs.o
> perf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
> perf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
> diff --git a/tools/perf/arch/loongarch/util/header.c b/tools/perf/arch/loongarch/util/header.c
> new file mode 100644
> index 000000000000..8f7061cf6977
> --- /dev/null
> +++ b/tools/perf/arch/loongarch/util/header.c
> @@ -0,0 +1,85 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Implementation of get_cpuid().
> + *
> + * Author: Nikita Shubin <n.shubin@xxxxxxxxx>
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <api/fs/fs.h>
> +#include <errno.h>
> +#include "util/debug.h"
> +#include "util/header.h"
> +
> +#define CPUINFO_MODEL "Model Name"
> +#define CPUINFO "/proc/cpuinfo"
> +
> +static char *_get_field(const char *line)
> +{
> + char *line2, *nl;
> +
> + line2 = strrchr(line, ' ');
> + if (!line2)
> + return NULL;
> +
> + line2++;
> + nl = strrchr(line, '\n');
> + if (!nl)
> + return NULL;
> +
> + return strndup(line2, nl - line2);
> +}
> +
> +static char *_get_cpuid(void)
> +{
> + char *line = NULL;
> + char *model = NULL;
> + char *cpuid = NULL;
> + int read;
> + unsigned long line_sz;
> + FILE *cpuinfo;
> +
> + cpuinfo = fopen(CPUINFO, "r");
> + if (cpuinfo == NULL)
> + return cpuid;
> +
> + while ((read = getline(&line, &line_sz, cpuinfo)) != -1) {
> + if (strncmp(line, CPUINFO_MODEL, strlen(CPUINFO_MODEL)))
> + continue;
> +
> + model = _get_field(line);
> + if (!model)
> + goto free;
> + break;
> + }
> +
> + if (asprintf(&cpuid, "%s", model) < 0)
> + cpuid = NULL;
> +
> +free:
> + fclose(cpuinfo);
> + free(model);
> + return cpuid;
> +}
> +
> +int get_cpuid(char *buffer, size_t sz)
> +{
> + char *cpuid = _get_cpuid();
> + int ret = 0;
> +
> + if (sz < strlen(cpuid)) {

Could this not segfault if cpuid is NULL?

Thanks,
Ian

> + ret = -EINVAL;
> + goto free;
> + }
> +
> + scnprintf(buffer, sz, "%s", cpuid);
> +free:
> + free(cpuid);
> + return ret;
> +}
> +
> +char *get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
> +{
> + return _get_cpuid();
> +}
> diff --git a/tools/perf/arch/loongarch/util/kvm-stat.c b/tools/perf/arch/loongarch/util/kvm-stat.c
> new file mode 100644
> index 000000000000..2c21d73cd855
> --- /dev/null
> +++ b/tools/perf/arch/loongarch/util/kvm-stat.c
> @@ -0,0 +1,141 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <errno.h>
> +#include <memory.h>
> +#include <errno.h>
> +#include "util/kvm-stat.h"
> +#include "util/parse-events.h"
> +#include "util/debug.h"
> +#include "util/evsel.h"
> +#include "util/evlist.h"
> +#include "util/pmus.h"
> +
> +#define LOONGARCH_EXCEPTION_INT 0
> +#define LOONGARCH_EXCEPTION_PIL 1
> +#define LOONGARCH_EXCEPTION_PIS 2
> +#define LOONGARCH_EXCEPTION_PIF 3
> +#define LOONGARCH_EXCEPTION_PME 4
> +#define LOONGARCH_EXCEPTION_FPD 15
> +#define LOONGARCH_EXCEPTION_SXD 16
> +#define LOONGARCH_EXCEPTION_ASXD 17
> +#define LOONGARCH_EXCEPTION_GSPR 22
> +#define LOONGARCH_EXCEPTION_CPUCFG 100
> +#define LOONGARCH_EXCEPTION_CSR 101
> +#define LOONGARCH_EXCEPTION_IOCSR 102
> +#define LOONGARCH_EXCEPTION_IDLE 103
> +#define LOONGARCH_EXCEPTION_OTHERS 104
> +#define LOONGARCH_EXCEPTION_HVC 23
> +
> +#define loongarch_exception_type \
> + {LOONGARCH_EXCEPTION_INT, "Interrupt" }, \
> + {LOONGARCH_EXCEPTION_PIL, "Mem read" }, \
> + {LOONGARCH_EXCEPTION_PIS, "Mem store" }, \
> + {LOONGARCH_EXCEPTION_PIF, "Ifecth" }, \
> + {LOONGARCH_EXCEPTION_PME, "Mem modify" }, \
> + {LOONGARCH_EXCEPTION_FPD, "FPU" }, \
> + {LOONGARCH_EXCEPTION_SXD, "LSX" }, \
> + {LOONGARCH_EXCEPTION_ASXD, "LASX" }, \
> + {LOONGARCH_EXCEPTION_GSPR, "Privilege Error" }, \
> + {LOONGARCH_EXCEPTION_HVC, "Hypercall" }, \
> + {LOONGARCH_EXCEPTION_CPUCFG, "Cpucfg" }, \
> + {LOONGARCH_EXCEPTION_CSR, "Csr" }, \
> + {LOONGARCH_EXCEPTION_IOCSR, "Iocsr" }, \
> + {LOONGARCH_EXCEPTION_IDLE, "Idle" }, \
> + {LOONGARCH_EXCEPTION_OTHERS, "Others" }
> +
> +
> +define_exit_reasons_table(loongarch_exit_reasons, loongarch_exception_type);
> +
> +const char *vcpu_id_str = "vcpu_id";
> +const char *kvm_exit_reason = "reason";
> +const char *kvm_entry_trace = "kvm:kvm_enter";
> +const char *kvm_reenter_trace = "kvm:kvm_reenter";
> +const char *kvm_exit_trace = "kvm:kvm_exit";
> +
> +const char *kvm_events_tp[] = {
> + "kvm:kvm_enter",
> + "kvm:kvm_reenter",
> + "kvm:kvm_exit",
> + "kvm:kvm_exit_gspr",
> + NULL,
> +};
> +
> +static bool event_end(struct evsel *evsel,
> + struct perf_sample *sample __maybe_unused,
> + struct event_key *key __maybe_unused)
> +{
> + /*
> + * LoongArch kvm is a little different with other architectures
> + *
> + * There is kvm:kvm_reenter and kvm:kvm_enter event adjacent with
> + * kvm:kvm_exit event.
> + * kvm:kvm_reenter means returning to guest immediately
> + * kvm:kvm_enter means returning to vmm and then to guest
> + */
> + return evsel__name_is(evsel, kvm_entry_trace) ||
> + evsel__name_is(evsel, kvm_reenter_trace);
> +}
> +
> +static void event_gspr_get_key(struct evsel *evsel,
> + struct perf_sample *sample,
> + struct event_key *key)
> +{
> + unsigned int insn;
> +
> + key->key = LOONGARCH_EXCEPTION_OTHERS;
> + insn = evsel__intval(evsel, sample, "inst_word");
> + switch (insn >> 24) {
> + case 0:
> + /* cpucfg inst trap */
> + if ((insn >> 10) == 0x1b)
> + key->key = LOONGARCH_EXCEPTION_CPUCFG;
> + break;
> + case 4:
> + /* csr inst trap */
> + key->key = LOONGARCH_EXCEPTION_CSR;
> + break;
> + case 6:
> + /* iocsr inst trap */
> + if ((insn >> 15) == 0xc90)
> + key->key = LOONGARCH_EXCEPTION_IOCSR;
> + else if ((insn >> 15) == 0xc91)
> + /* idle inst trap */
> + key->key = LOONGARCH_EXCEPTION_IDLE;
> + break;
> + default:
> + key->key = LOONGARCH_EXCEPTION_OTHERS;
> + break;
> + }
> +}
> +
> +static struct child_event_ops child_events[] = {
> + { .name = "kvm:kvm_exit_gspr",
> + .get_key = event_gspr_get_key },
> + { NULL, NULL },
> +};
> +
> +static struct kvm_events_ops exit_events = {
> + .is_begin_event = exit_event_begin,
> + .is_end_event = event_end,
> + .child_ops = child_events,
> + .decode_key = exit_event_decode_key,
> + .name = "VM-EXIT"
> +};
> +
> +struct kvm_reg_events_ops kvm_reg_events_ops[] = {
> + {
> + .name = "vmexit",
> + .ops = &exit_events,
> + },
> + { NULL, NULL },
> +};
> +
> +const char * const kvm_skip_events[] = {
> + NULL,
> +};
> +
> +int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid __maybe_unused)
> +{
> + kvm->exit_reasons_isa = "loongarch64";
> + kvm->exit_reasons = loongarch_exit_reasons;
> + return 0;
> +}
>
> base-commit: f2f80ac809875855ac843f9e5e7480604b5cbff5
> --
> 2.39.3
>
>

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In reply to: Bibo Mao: "[PATCH v2] perf kvm: Add kvm-stat for loongarch64"
Next in thread: maobibo: "Re: [PATCH v2] perf kvm: Add kvm-stat for loongarch64"
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