lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-Id: <9e5b7638ff44111334aff53b76bdcd1f26f08179.1526901337.git.robin.murphy@arm.com>
Date:   Mon, 21 May 2018 12:17:09 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     will.deacon@....com, mark.rutland@....com
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] perf/arm-cci: Remove unnecessary period adjustment

Since sampling events are rejected up-front by cci_pmu_event_init(), it
doesn't make much sense to go fiddling with the sampling period later.
This would seem to be just another leftover artefact of the arm_pmu
framwork, and as such can go.

Acked-by: Mark Rutland <mark.rutland@....com>
Signed-off-by: Robin Murphy <robin.murphy@....com>
---
 drivers/perf/arm-cci.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c
index 09938dd8eb6f..e6fadc8e1178 100644
--- a/drivers/perf/arm-cci.c
+++ b/drivers/perf/arm-cci.c
@@ -1297,15 +1297,6 @@ static int __hw_perf_event_init(struct perf_event *event)
 	 */
 	hwc->config_base	    |= (unsigned long)mapping;
 
-	/*
-	 * Limit the sample_period to half of the counter width. That way, the
-	 * new counter value is far less likely to overtake the previous one
-	 * unless you have some serious IRQ latency issues.
-	 */
-	hwc->sample_period  = CCI_PMU_CNTR_MASK >> 1;
-	hwc->last_period    = hwc->sample_period;
-	local64_set(&hwc->period_left, hwc->sample_period);
-
 	if (event->group_leader != event) {
 		if (validate_group(event) != 0)
 			return -EINVAL;
-- 
2.17.0.dirty

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ