From: kan.liang@linux.intel.com
To: peterz@infradead.org, acme@kernel.org, mingo@redhat.com,
linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de, jolsa@kernel.org, eranian@google.com,
alexander.shishkin@linux.intel.com, ak@linux.intel.com
Subject: [PATCH V4 06/14] x86/math64: Provide a sane mul_u64_u32_div() implementation for x86_64
Date: Mon, 16 Sep 2019 06:41:20 -0700 [thread overview]
Message-ID: <20190916134128.18120-7-kan.liang@linux.intel.com> (raw)
In-Reply-To: <20190916134128.18120-1-kan.liang@linux.intel.com>
From: "Peter Zijlstra (Intel)" <peterz@infradead.org>
On x86_64 we can do a u64 * u64 -> u128 widening multiply followed by
a u128 / u64 -> u64 division to implement a sane version of
mul_u64_u32_div().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
New patch for V4
arch/x86/include/asm/div64.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/x86/include/asm/div64.h b/arch/x86/include/asm/div64.h
index 20a46150e0a8..9b8cb50768c2 100644
--- a/arch/x86/include/asm/div64.h
+++ b/arch/x86/include/asm/div64.h
@@ -73,6 +73,19 @@ static inline u64 mul_u32_u32(u32 a, u32 b)
#else
# include <asm-generic/div64.h>
+
+static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 div)
+{
+ u64 q;
+
+ asm ("mulq %2; divq %3" : "=a" (q)
+ : "a" (a), "rm" ((u64)mul), "rm" ((u64)div)
+ : "rdx");
+
+ return q;
+}
+#define mul_u64_u32_div mul_u64_u32_div
+
#endif /* CONFIG_X86_32 */
#endif /* _ASM_X86_DIV64_H */
--
2.17.1
next prev parent reply other threads:[~2019-09-16 13:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-16 13:41 [PATCH V4 00/14] TopDown metrics support for Icelake kan.liang
2019-09-16 13:41 ` [PATCH V4 01/14] perf/x86/intel: Introduce the fourth fixed counter kan.liang
2019-09-16 13:41 ` [PATCH V4 02/14] perf/x86/intel: Set correct mask for TOPDOWN.SLOTS kan.liang
2019-09-16 13:41 ` [PATCH V4 03/14] perf/x86/intel: Move BTS index to 47 kan.liang
2019-09-16 13:41 ` [PATCH V4 04/14] perf/x86/intel: Basic support for metrics counters kan.liang
2019-09-16 13:41 ` [PATCH V4 05/14] perf/x86/intel: Fix the name of perf capabilities for perf METRICS kan.liang
2019-09-16 13:41 ` kan.liang [this message]
2019-09-16 13:41 ` [PATCH V4 07/14] perf/x86/intel: Support hardware TopDown metrics kan.liang
2019-09-30 13:06 ` Peter Zijlstra
2019-09-30 14:07 ` Peter Zijlstra
2019-09-30 14:53 ` Peter Zijlstra
2019-09-30 16:17 ` Liang, Kan
2019-09-30 16:21 ` Peter Zijlstra
2019-09-30 16:45 ` Liang, Kan
2019-09-30 18:18 ` Andi Kleen
2019-09-30 13:36 ` Peter Zijlstra
2019-09-16 13:41 ` [PATCH V4 08/14] perf/x86/intel: Support per thread RDPMC " kan.liang
2019-09-30 15:52 ` Peter Zijlstra
2019-09-30 18:18 ` Liang, Kan
2019-09-16 13:41 ` [PATCH V4 09/14] perf/x86/intel: Export TopDown events for Icelake kan.liang
2019-09-16 13:41 ` [PATCH V4 10/14] perf/x86/intel: Disable sampling read slots and topdown kan.liang
2019-09-16 13:41 ` [PATCH V4 11/14] perf/x86/intel: Name global status bit in NMI handler kan.liang
2019-09-16 13:41 ` [PATCH V4 12/14] perf/x86: Use event_base_rdpmc for RDPMC userspace support kan.liang
2019-09-16 13:41 ` [PATCH V4 13/14] perf, tools, stat: Support new per thread TopDown metrics kan.liang
2019-09-16 13:41 ` [PATCH V4 14/14] perf, tools: Add documentation for topdown metrics kan.liang
2019-09-30 12:48 ` [PATCH V4 00/14] TopDown metrics support for Icelake Liang, Kan
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