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 <[email protected]>
Cc: <[email protected]> #3.12+
Signed-off-by: Yang Shi <[email protected]>
---
V2 --> V1:
* Remove double new line and unnecessary bogomips sum info
arch/arm64/kernel/cpuinfo.c | 5 +++++
1 file changed, 5 insertions(+)
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)
--
2.0.2
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 <[email protected]>
> Cc: <[email protected]> #3.12+
> Signed-off-by: Yang Shi <[email protected]>
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.
--
Catalin
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 <[email protected]>
>> Cc: <[email protected]> #3.12+
>> Signed-off-by: Yang Shi <[email protected]>
>
> 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.
>