Em Mon, Jun 10, 2019 at 12:15:17PM +0530, Anju T Sudhakar escreveu:
> 'perf kvm record' uses 'cycles'(if the user did not specify any event) as
> the default event to profile the guest.
> This will not provide any proper samples from the guest incase of
> powerpc architecture, since in powerpc the PMUs are controlled by
> the guest rather than the host.
>
> Patch adds a function to pick an arch specific event for 'perf kvm record',
> instead of selecting 'cycles' as a default event for all architectures.
>
> For powerpc this function checks for any user specified event, and if there
> isn't any it returns invalid instead of proceeding with 'cycles' event.
Michael, Ravi, Maddy, could you please provide an Acked-by, Reviewed-by
or Tested-by?
- Arnaldo
> Signed-off-by: Anju T Sudhakar <a...@linux.vnet.ibm.com>
> ---
> tools/perf/arch/powerpc/util/kvm-stat.c | 37 +++++++++++++++++++++++++
> tools/perf/builtin-kvm.c | 12 +++++++-
> tools/perf/util/kvm-stat.h | 2 +-
> 3 files changed, 49 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/arch/powerpc/util/kvm-stat.c
> b/tools/perf/arch/powerpc/util/kvm-stat.c
> index f9db341c47b6..66f8fe500945 100644
> --- a/tools/perf/arch/powerpc/util/kvm-stat.c
> +++ b/tools/perf/arch/powerpc/util/kvm-stat.c
> @@ -8,6 +8,7 @@
>
> #include "book3s_hv_exits.h"
> #include "book3s_hcalls.h"
> +#include <subcmd/parse-options.h>
>
> #define NR_TPS 4
>
> @@ -172,3 +173,39 @@ int cpu_isa_init(struct perf_kvm_stat *kvm, const char
> *cpuid __maybe_unused)
>
> return ret;
> }
> +
> +/*
> + * Incase of powerpc architecture, pmu registers are programmable
> + * by guest kernel. So monitoring guest via host may not provide
> + * valid samples. It is better to fail the "perf kvm record"
> + * with default "cycles" event to monitor guest in powerpc.
> + *
> + * Function to parse the arguments and return appropriate values.
> + */
> +int kvm_add_default_arch_event(int *argc, const char **argv)
> +{
> + const char **tmp;
> + bool event = false;
> + int i, j = *argc;
> +
> + const struct option event_options[] = {
> + OPT_BOOLEAN('e', "event", &event, NULL),
> + OPT_END()
> + };
> +
> + tmp = calloc(j + 1, sizeof(char *));
> + if (!tmp)
> + return -EINVAL;
> +
> + for (i = 0; i < j; i++)
> + tmp[i] = argv[i];
> +
> + parse_options(j, tmp, event_options, NULL, 0);
> + if (!event) {
> + free(tmp);
> + return -EINVAL;
> + }
> +
> + free(tmp);
> + return 0;
> +}
> diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
> index dbb6f737a3e2..fe33b3ec55c9 100644
> --- a/tools/perf/builtin-kvm.c
> +++ b/tools/perf/builtin-kvm.c
> @@ -1510,11 +1510,21 @@ static int kvm_cmd_stat(const char *file_name, int
> argc, const char **argv)
> }
> #endif /* HAVE_KVM_STAT_SUPPORT */
>
> +int __weak kvm_add_default_arch_event(int *argc __maybe_unused,
> + const char **argv __maybe_unused)
> +{
> + return 0;
> +}
> +
> static int __cmd_record(const char *file_name, int argc, const char **argv)
> {
> - int rec_argc, i = 0, j;
> + int rec_argc, i = 0, j, ret;
> const char **rec_argv;
>
> + ret = kvm_add_default_arch_event(&argc, argv);
> + if (ret)
> + return -EINVAL;
> +
> rec_argc = argc + 2;
> rec_argv = calloc(rec_argc + 1, sizeof(char *));
> rec_argv[i++] = strdup("record");
> diff --git a/tools/perf/util/kvm-stat.h b/tools/perf/util/kvm-stat.h
> index 1403dec189b4..da38b56c46cb 100644
> --- a/tools/perf/util/kvm-stat.h
> +++ b/tools/perf/util/kvm-stat.h
> @@ -144,5 +144,5 @@ extern const int decode_str_len;
> extern const char *kvm_exit_reason;
> extern const char *kvm_entry_trace;
> extern const char *kvm_exit_trace;
> -
> +extern int kvm_add_default_arch_event(int *argc, const char **argv);
> #endif /* __PERF_KVM_STAT_H */
> --
> 2.17.2
--
- Arnaldo
