[PATCH] arm64: restore bogomips information in /proc/cpuinfo
will.deacon at arm.com
Wed Nov 18 10:47:36 PST 2015
On Wed, Nov 18, 2015 at 10:15:05AM -0800, Yang Shi wrote:
> As what Pavel Machek reported , 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.
>  https://lkml.org/lkml/2015/1/4/132
I lost this argument last time around, so I won't re-tread that path this
time around. I do, however, have some comments on the patch.
> Signed-off-by: Yang Shi <yang.shi at linaro.org>
> arch/arm64/kernel/cpuinfo.c | 5 +++++
> arch/arm64/kernel/smp.c | 7 ++++++-
> 2 files changed, 11 insertions(+), 1 deletion(-)
> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
> index 706679d..8d4ba77 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\n",
This double newline makes /proc/cpuinfo looks really odd. Can we just
have one, please?
> + 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)
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index b1adc51..1bed772 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -326,7 +326,12 @@ static void __init hyp_mode_check(void)
> void __init smp_cpus_done(unsigned int max_cpus)
> - pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
> + unsigned long bogosum = loops_per_jiffy * num_online_cpus();
> + pr_info("SMP: Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
> + num_online_cpus(), bogosum / (500000/HZ),
> + (bogosum / (5000/HZ)) % 100);
Can we drop this hunk? I don't see a pressing need to print this in
With those two changes:
Acked-by: Will Deacon <will.deacon at arm.com>
I guess this needs Cc'ing to stable, too.
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