[tip:perf/core] Revert "ARM: 7556/1: perf: fix updated event period in response to PERF_EVENT_IOC_PERIOD"

[tip-bot for Will Deacon <tipbot@zytor.com>]

Commit-ID:  9450d14fb959336803e5209119eb422b667b96aa
Gitweb:     http://git.kernel.org/tip/9450d14fb959336803e5209119eb422b667b96aa
Author:     Will Deacon <will.deacon@arm.com>
AuthorDate: Wed, 27 Nov 2013 13:54:39 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 17 Dec 2013 15:21:35 +0100

Revert "ARM: 7556/1: perf: fix updated event period in response to PERF_EVENT_IOC_PERIOD"

This reverts commit 3581fe0ef37ce12ac7a4f74831168352ae848edc.

Fixes to the handling of PERF_EVENT_IOC_PERIOD in the core code mean
we no longer have to play this horrible game.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1385560479-11014-2-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/arm/kernel/perf_event.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index bc3f2ef..789d846 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -99,10 +99,6 @@ int armpmu_event_set_period(struct perf_event *event)
 	s64 period = hwc->sample_period;
 	int ret = 0;
 
-	/* The period may have been changed by PERF_EVENT_IOC_PERIOD */
-	if (unlikely(period != hwc->last_period))
-		left = period - (hwc->last_period - left);
-
 	if (unlikely(left <= -period)) {
 		left = period;
 		local64_set(&hwc->period_left, left);