From: "tip-bot2 for Andrei Vagin" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Andrei Vagin <avagin@gmail.com>, Dmitry Safonov <dima@arista.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [tip: timers/core] lib/vdso: Add unlikely() hint into vdso_read_begin()
Date: Tue, 14 Jan 2020 13:02:21 -0000 [thread overview]
Message-ID: <157900694182.396.7317245698393381452.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20191112012724.250792-2-dima@arista.com>
The following commit has been merged into the timers/core branch of tip:
Commit-ID: 0898a16a362d436464b34fa644d0d46efc81df92
Gitweb: https://git.kernel.org/tip/0898a16a362d436464b34fa644d0d46efc81df92
Author: Andrei Vagin <avagin@gmail.com>
AuthorDate: Tue, 12 Nov 2019 01:26:50
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 14 Jan 2020 12:20:47 +01:00
lib/vdso: Add unlikely() hint into vdso_read_begin()
Place the branch with no concurrent write before the contended case.
Performance numbers for Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz
(more clock_gettime() cycles - the better):
| before | after
-----------------------------------
| 150252214 | 153242367
| 150301112 | 153324800
| 150392773 | 153125401
| 150373957 | 153399355
| 150303157 | 153489417
| 150365237 | 153494270
-----------------------------------
avg | 150331408 | 153345935
diff % | 2 | 0
-----------------------------------
stdev % | 0.3 | 0.1
Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20191112012724.250792-2-dima@arista.com
---
include/vdso/helpers.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/vdso/helpers.h b/include/vdso/helpers.h
index 01641db..9a2af9f 100644
--- a/include/vdso/helpers.h
+++ b/include/vdso/helpers.h
@@ -10,7 +10,7 @@ static __always_inline u32 vdso_read_begin(const struct vdso_data *vd)
{
u32 seq;
- while ((seq = READ_ONCE(vd->seq)) & 1)
+ while (unlikely((seq = READ_ONCE(vd->seq)) & 1))
cpu_relax();
smp_rmb();
next prev parent reply other threads:[~2020-01-14 13:03 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 1:26 [PATCHv8 00/34] kernel: Introduce Time Namespace Dmitry Safonov
2019-11-12 1:26 ` [PATCHv8 01/34] lib/vdso: Add unlikely() hint into vdso_read_begin() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin [this message]
2019-11-12 1:26 ` [PATCHv8 02/34] lib/vdso: make do_hres and do_coarse as __always_inline Dmitry Safonov
2020-01-10 9:45 ` Vincenzo Frascino
2020-01-10 11:42 ` Thomas Gleixner
2020-01-10 11:47 ` Vincenzo Frascino
2020-01-10 12:02 ` Thomas Gleixner
2020-01-10 12:18 ` Vincenzo Frascino
2020-01-13 5:27 ` Andrei Vagin
2020-01-13 19:09 ` [tip: timers/core] lib/vdso: Mark do_hres() and do_coarse() " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 03/34] ns: Introduce Time Namespace Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2020-01-27 14:12 ` [PATCHv8 03/34] " Dmitry Vyukov
2020-01-27 14:19 ` Dmitry Safonov
2020-02-17 14:20 ` Time Namespaces: CLONE_NEWTIME and clone3()? Michael Kerrisk
2020-02-17 14:59 ` Christian Brauner
2020-02-17 21:47 ` Michael Kerrisk (man-pages)
2020-02-17 23:03 ` Christian Brauner
2020-02-17 23:29 ` Thomas Gleixner
2020-02-18 2:37 ` Eric W. Biederman
2020-02-18 17:11 ` Adrian Reber
2020-02-18 17:26 ` Christian Brauner
2019-11-12 1:26 ` [PATCHv8 04/34] time: Add timens_offsets to be used for tasks in timens Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] time: Add timens_offsets to be used for tasks in time namespace tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 05/34] posix-clocks: Rename the clock_get() callback to clock_get_timespec() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 06/34] posix-clocks: Rename .clock_get_timespec() callbacks accordingly Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 07/34] alarmtimer: Rename gettime() callback to get_ktime() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 08/34] alarmtimer: Provide get_timespec() callback Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 09/34] posix-clocks: Introduce clock_get_ktime() callback Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 10/34] posix-timers: Use clock_get_ktime() in common_timer_get() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 11/34] posix-clocks: Wire up clock_gettime() with timens offsets Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 12/34] kernel: Add do_timens_ktime_to_host() helper Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] time: " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 13/34] timerfd: Make timerfd_settime() time namespace aware Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 14/34] posix-timers: Make timer_settime() " Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 15/34] alarmtimer: Make nanosleep " Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] alarmtimer: Make nanosleep() " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 16/34] hrtimers: Prepare hrtimer_nanosleep() for time namespaces Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 17/34] posix-timers: Make clock_nanosleep() time namespace aware Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 18/34] fs/proc: Respect boottime inside time namespace for /proc/uptime Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 19/34] x86/vdso: Restrict splitting VVAR VMA Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 20/34] lib/vdso: Prepare for time namespace support Dmitry Safonov
2020-01-12 10:32 ` Thomas Gleixner
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-01-14 13:02 ` tip-bot2 for Thomas Gleixner
2019-11-12 1:27 ` [PATCHv8 21/34] x86/vdso: Provide vdso_data offset on vvar_page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 22/34] x86/vdso: Add timens page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] x86/vdso: Add time napespace page tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 23/34] time: Allocate per-timens vvar page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 24/34] x86/vdso: Handle faults on timens page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 25/34] x86/vdso: On timens page fault prefault also VVAR page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 26/34] x86/vdso: Zap vvar pages on switch a time namspace Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] x86/vdso: Zap vvar pages when switching to a time namespace tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 27/34] fs/proc: Introduce /proc/pid/timens_offsets Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 28/34] selftests/timens: Add Time Namespace test for supported clocks Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 29/34] selftests/timens: Add a test for timerfd Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 30/34] selftests/timens: Add a test for clock_nanosleep() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 31/34] selftests/timens: Add procfs selftest Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 32/34] selftests/timens: Add timer offsets test Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 33/34] selftests/timens: Add a simple perf test for clock_gettime() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 34/34] selftests/timens: Check for right timens offsets after fork and exec Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-21 18:05 ` [PATCHv8 00/34] kernel: Introduce Time Namespace Andrei Vagin
2019-12-11 20:38 ` Dmitry Safonov
2020-01-09 21:09 ` Thomas Gleixner
2020-01-10 9:52 ` Vincenzo Frascino
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