public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, Dave Jones <davej@codemonkey.org.uk>
Subject: [PATCH RFC] x86: fix confusing name of /proc/cpuinfo "ht" flag
Date: Wed, 11 Nov 2009 21:34:34 +0100	[thread overview]
Message-ID: <200911112134.34261.bzolnier@gmail.com> (raw)


"ht" flag indicates only ability to detect siblings not HT presence itself.

Inspired by:
http://www.codemonkey.org.uk/2009/11/10/common-hyperthreading-misconception/

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
It could be that there are some user-space programs depending on "ht"
flag so the patch is marked as RFC..

 arch/x86/include/asm/cpufeature.h |    4 ++--
 arch/x86/kernel/cpu/capflags.c    |    2 +-
 arch/x86/kernel/cpu/common.c      |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

Index: b/arch/x86/include/asm/cpufeature.h
===================================================================
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -42,7 +42,7 @@
 #define X86_FEATURE_XMM		(0*32+25) /* "sse" */
 #define X86_FEATURE_XMM2	(0*32+26) /* "sse2" */
 #define X86_FEATURE_SELFSNOOP	(0*32+27) /* "ss" CPU self snoop */
-#define X86_FEATURE_HT		(0*32+28) /* Hyper-Threading */
+#define X86_FEATURE_HT_DETECTION (0*32+28) /* Hyper-Threading detection */
 #define X86_FEATURE_ACC		(0*32+29) /* "tm" Automatic clock control */
 #define X86_FEATURE_IA64	(0*32+30) /* IA-64 processor */
 #define X86_FEATURE_PBE		(0*32+31) /* Pending Break Enable */
@@ -220,7 +220,7 @@ extern const char * const x86_power_flag
 #define cpu_has_xmm2		boot_cpu_has(X86_FEATURE_XMM2)
 #define cpu_has_xmm3		boot_cpu_has(X86_FEATURE_XMM3)
 #define cpu_has_aes		boot_cpu_has(X86_FEATURE_AES)
-#define cpu_has_ht		boot_cpu_has(X86_FEATURE_HT)
+#define cpu_has_ht_detection	boot_cpu_has(X86_FEATURE_HT_DETECTION)
 #define cpu_has_mp		boot_cpu_has(X86_FEATURE_MP)
 #define cpu_has_nx		boot_cpu_has(X86_FEATURE_NX)
 #define cpu_has_k6_mtrr		boot_cpu_has(X86_FEATURE_K6_MTRR)
Index: b/arch/x86/kernel/cpu/capflags.c
===================================================================
--- a/arch/x86/kernel/cpu/capflags.c
+++ b/arch/x86/kernel/cpu/capflags.c
@@ -27,7 +27,7 @@ const char * const x86_cap_flags[NCAPINT
 	[X86_FEATURE_XMM]                = "sse",
 	[X86_FEATURE_XMM2]               = "sse2",
 	[X86_FEATURE_SELFSNOOP]          = "ss",
-	[X86_FEATURE_HT]                 = "ht",
+	[X86_FEATURE_HT_DETECTION]       = "ht_detection",
 	[X86_FEATURE_ACC]                = "tm",
 	[X86_FEATURE_IA64]               = "ia64",
 	[X86_FEATURE_PBE]                = "pbe",
Index: b/arch/x86/kernel/cpu/common.c
===================================================================
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -433,7 +433,7 @@ void __cpuinit detect_ht(struct cpuinfo_
 	u32 eax, ebx, ecx, edx;
 	int index_msb, core_bits;
 
-	if (!cpu_has(c, X86_FEATURE_HT))
+	if (!cpu_has(c, X86_FEATURE_HT_DETECTION))
 		return;
 
 	if (cpu_has(c, X86_FEATURE_CMP_LEGACY))

             reply	other threads:[~2009-11-11 20:35 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-11 20:34 Bartlomiej Zolnierkiewicz [this message]
2009-11-11 20:46 ` [PATCH RFC] x86: fix confusing name of /proc/cpuinfo "ht" flag Chris Friesen
2009-11-12 17:07   ` Alexander Clouter
2009-11-11 21:35 ` Jeff Garzik
2009-11-12  6:59 ` Ingo Molnar
2009-11-12  7:08   ` H. Peter Anvin
2009-11-12  8:13     ` Ingo Molnar
2009-11-12 15:18       ` H. Peter Anvin
2009-11-12 17:59         ` Ingo Molnar
2009-11-12 18:37           ` Dave Jones
2009-11-12 19:49             ` H. Peter Anvin
2009-11-13  7:42               ` Ingo Molnar
2009-11-13 10:24                 ` Bartlomiej Zolnierkiewicz
2009-11-13  7:17           ` H. Peter Anvin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=200911112134.34261.bzolnier@gmail.com \
    --to=bzolnier@gmail.com \
    --cc=davej@codemonkey.org.uk \
    --cc=linux-kernel@vger.kernel.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox