linux-kernel - [PATCH 2/2] tools/perf: Set 'trace_cycles' as defaultevent for perf kvm record in powerpc

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Message-Id: <20190524105107.324-2-anju@linux.vnet.ibm.com>
Date:   Fri, 24 May 2019 16:21:07 +0530
From:   Anju T Sudhakar <anju@...ux.vnet.ibm.com>
To:     mpe@...erman.id.au
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        anju@...ux.vnet.ibm.com, maddy@...ux.vnet.ibm.com
Subject: [PATCH 2/2] tools/perf: Set 'trace_cycles' as defaultevent for perf kvm record in powerpc

Use 'trace_imc/trace_cycles' as the default event for 'perf kvm record'
in powerpc.

Signed-off-by: Anju T Sudhakar <anju@...ux.vnet.ibm.com>
---
 tools/perf/arch/powerpc/util/kvm-stat.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/tools/perf/arch/powerpc/util/kvm-stat.c b/tools/perf/arch/powerpc/util/kvm-stat.c
index 66f8fe500945..b552884263df 100644
--- a/tools/perf/arch/powerpc/util/kvm-stat.c
+++ b/tools/perf/arch/powerpc/util/kvm-stat.c
@@ -177,8 +177,9 @@ int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid __maybe_unused)
 /*
  * 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.
+ * valid samples with default 'cycles' event. It is better to use
+ * 'trace_imc/trace_cycles' event for guest profiling, since it
+ * can track the guest instruction pointer in the trace-record.
  *
  * Function to parse the arguments and return appropriate values.
  */
@@ -202,8 +203,14 @@ int kvm_add_default_arch_event(int *argc, const char **argv)
 
 	parse_options(j, tmp, event_options, NULL, 0);
 	if (!event) {
-		free(tmp);
-		return -EINVAL;
+		if (pmu_have_event("trace_imc", "trace_cycles")) {
+			argv[j++] = strdup("-e");
+			argv[j++] = strdup("trace_imc/trace_cycles/");
+			*argc += 2;
+		} else {
+			free(tmp);
+			return -EINVAL;
+		}
 	}
 
 	free(tmp);
-- 
2.17.2