diff mbox

[V2] arm64: restore bogomips information in /proc/cpuinfo

Message ID 1447872535-31117-1-git-send-email-yang.shi@linaro.org
State Accepted
Commit 92e788b749862ebe9920360513a718e5dd4da7a9
Headers show

Commit Message

Yang Shi Nov. 18, 2015, 6:48 p.m. UTC
As what Pavel Machek reported [1], some userspace applications depend on
bogomips showed by /proc/cpuinfo.

Although there is much less legacy impact on aarch64 than arm, but it does
break libvirt.

Basically, this patch reverts commit 326b16db9f69fd0d279be873c6c00f88c0a4aad5
("arm64: delay: don't bother reporting bogomips in /proc/cpuinfo"), but with
some tweak due to context change.

[1] https://lkml.org/lkml/2015/1/4/132

Acked-by: Will Deacon <will.deacon@arm.com>

Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: Yang Shi <yang.shi@linaro.org>

---
V2 --> V1:
* Remove double new line and unnecessary bogomips sum info

 arch/arm64/kernel/cpuinfo.c | 5 +++++
 1 file changed, 5 insertions(+)

-- 
2.0.2

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Comments

Yang Shi Nov. 20, 2015, 12:23 a.m. UTC | #1
On 11/19/2015 9:59 AM, Catalin Marinas wrote:
> On Wed, Nov 18, 2015 at 10:48:55AM -0800, Yang Shi wrote:

>> As what Pavel Machek reported [1], some userspace applications depend on

>> bogomips showed by /proc/cpuinfo.

>>

>> Although there is much less legacy impact on aarch64 than arm, but it does

>> break libvirt.

>>

>> Basically, this patch reverts commit 326b16db9f69fd0d279be873c6c00f88c0a4aad5

>> ("arm64: delay: don't bother reporting bogomips in /proc/cpuinfo"), but with

>> some tweak due to context change.

>>

>> [1] https://lkml.org/lkml/2015/1/4/132

>>

>> Acked-by: Will Deacon <will.deacon@arm.com>

>> Cc: <stable@vger.kernel.org> #3.12+

>> Signed-off-by: Yang Shi <yang.shi@linaro.org>

>

> Patch applied as a fix for stable, basically returning back to the

> pre-3.12 behaviour. If there is a need for some more useful information

> here, it can be done as an additional patch, though without cc: stable.


Thanks. This approach sounds safer to usersapce.

Yang

>

> Thanks.

>


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diff mbox

Patch

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 706679d..212ae63 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -30,6 +30,7 @@ 
 #include <linux/seq_file.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
+#include <linux/delay.h>
 
 /*
  * In case the boot CPU is hotpluggable, we record its initial state and
@@ -112,6 +113,10 @@  static int c_show(struct seq_file *m, void *v)
 		 */
 		seq_printf(m, "processor\t: %d\n", i);
 
+		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
+			   loops_per_jiffy / (500000UL/HZ),
+			   loops_per_jiffy / (5000UL/HZ) % 100);
+
 		/*
 		 * Dump out the common processor features in a single line.
 		 * Userspace should read the hwcaps with getauxval(AT_HWCAP)