From: Jed Davis <jld@mozilla.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Will Deacon <will.deacon@arm.com>,
Russell King <linux@arm.linux.org.uk>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] perf: ARM: Record the user-mode PC in the call chain.
Date: Thu, 13 Jun 2013 16:21:11 -0700 [thread overview]
Message-ID: <20130613232111.GA12536@mozilla.com> (raw)
With this change, we no longer lose the innermost entry in the user-mode
part of the call chain. See also the x86 port, which includes the ip.
It's possible to partially work around this problem by post-processing
the data to use the PERF_SAMPLE_IP value, but this works only if the CPU
wasn't in the kernel when the sample was taken.
Signed-off-by: Jed Davis <jld@mozilla.com>
---
arch/arm/kernel/perf_event.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 8c3094d..d9f5cd4 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -569,6 +569,7 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
return;
}
+ perf_callchain_store(entry, regs->ARM_pc);
tail = (struct frame_tail __user *)regs->ARM_fp - 1;
while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
--
1.7.10.4
next reply other threads:[~2013-06-13 23:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-13 23:21 Jed Davis [this message]
2013-06-18 13:13 ` [PATCH] perf: ARM: Record the user-mode PC in the call chain Will Deacon
2013-06-20 3:17 ` Jed Davis
2013-06-20 9:07 ` Will Deacon
2013-06-29 0:09 ` Sukadev Bhattiprolu
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