[PATCH 06/17] x86/tsc: Use the full 64-bit tsc in tsc_delay

From	Andy Lutomirski <luto@kernel.org>
Newsgroups	linux.kernel
Subject	[PATCH 06/17] x86/tsc: Use the full 64-bit tsc in tsc_delay
Date	2015-06-13 02:00 +0200
Message-ID	<pAH1E-4gk-17@gated-at.bofh.it> (permalink)
References	<pAGRX-44S-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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As a very minor optimization, tsc_delay was only using the low 32
bits of the TSC.  It's a delay function, so just use the whole
thing.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/lib/delay.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
index 9a52ad0c0758..35115f3786a9 100644
--- a/arch/x86/lib/delay.c
+++ b/arch/x86/lib/delay.c
@@ -49,16 +49,16 @@ static void delay_loop(unsigned long loops)
 /* TSC based delay: */
 static void delay_tsc(unsigned long __loops)
 {
-	u32 bclock, now, loops = __loops;
+	u64 bclock, now, loops = __loops;
 	int cpu;
 
 	preempt_disable();
 	cpu = smp_processor_id();
 	rdtsc_barrier();
-	rdtscl(bclock);
+	bclock = native_read_tsc();
 	for (;;) {
 		rdtsc_barrier();
-		rdtscl(now);
+		now = native_read_tsc();
 		if ((now - bclock) >= loops)
 			break;
 
@@ -80,7 +80,7 @@ static void delay_tsc(unsigned long __loops)
 			loops -= (now - bclock);
 			cpu = smp_processor_id();
 			rdtsc_barrier();
-			rdtscl(bclock);
+			bclock = native_read_tsc();
 		}
 	}
 	preempt_enable();
-- 
2.4.2

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Thread

[PATCH 00/17] x86/tsc: Clean up rdtsc helpers Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 13/17] x86/tsc: Rename native_read_tsc() to rdtsc_unordered() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 16/17] x86/tsc: Use rdtsc_ordered() in check_tsc_warp() and drop extra barriers Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 04/17] x86/tsc: Remove the rdtscp and rdtscpll macros Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 02/17] x86/msr/kvm: Remove vget_cycles() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 14/17] x86/tsc: Move rdtsc_barrier() and rename it to barrier_before_rdtsc() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 15/17] x86: Add rdtsc_ordered() and use it in trivial call sites Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 10/17] input/joystick/analog: Switch from rdtscl() to native_read_tsc() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 07/17] x86/cpu/amd: Use the full 64-bit TSC to detect the 2.6.2 bug Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 11/17] drivers/input/gameport: Replace rdtscl() with native_read_tsc() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 17/17] x86/tsc: In read_tsc, use rdtsc_ordered() instead of get_cycles() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 09/17] staging/lirc_serial: Remove TSC-based timing Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 16/17] x86/tsc: Use rdtsc_unordered() in check_tsc_warp() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 12/17] x86/tsc: Remove rdtscl() Andy Lutomirski <luto@kernel.org> - 2015-06-13 01:50 +0200
  [PATCH 03/17] x86/tsc: Replace rdtscll with native_read_tsc Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200
  [PATCH 01/17] x86/tsc: Inline native_read_tsc and remove __native_read_tsc Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200
  [PATCH 08/17] baycom_epp: Replace rdtscl() with native_read_tsc() Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200
  [PATCH 03/17] x86/tsc/paravirt: Remove the read_tsc and read_tscp paravirt hooks Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200
  [PATCH 05/17] x86/tsc: Remove the rdtscp and rdtscpll macros Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200
  [PATCH 06/17] x86/tsc: Use the full 64-bit tsc in tsc_delay Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200
  [PATCH 04/17] x86/tsc: Replace rdtscll with native_read_tsc Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200
  [PATCH 05/17] x86/tsc/paravirt: Remove the read_tsc and read_tscp paravirt hooks Andy Lutomirski <luto@kernel.org> - 2015-06-13 02:00 +0200

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