Re: [PATCH 2/2 V7] intel_pstate: add kernel parameter to force loading on Sun X86 servers.
From: ethan zhao
Date: Thu Dec 04 2014 - 21:23:37 EST
Kristen,
On 2014/12/5 6:38, Kristen Carlson Accardi wrote:
On Thu, 04 Dec 2014 23:10:58 +0100
"Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> wrote:
On Thursday, December 04, 2014 11:07:31 AM Ethan Zhao wrote:
To force loading on Oracle Sun X86 servers, provide one kernel command line
parameter
intel_pstate = ora_force
I would suggest to change the name of the option to "oracle_force" or "sun_force"
for clarity.
Anyway, I need an ACK from Kristen if this patch is to be applied.
For those who be aware of the risk of no power capping capabily working and
try to get better performance with this driver.
Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
---
v2: change to hardware vendor specific naming parameter.
v4: refine code and doc.
v5&v6: fix a typo in doc.
v7: change enum PCC to PPC.
Documentation/kernel-parameters.txt | 5 +++++
drivers/cpufreq/intel_pstate.c | 6 +++++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 479f332..7d0983e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1446,6 +1446,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
disable
Do not enable intel_pstate as the default
scaling driver for the supported processors
+ ora_force
+ Force loading intel_pstate on Oracle Sun Servers(X86).
+ only for those who be aware of the risk of no power capping
+ capability working and try to get better performance with this
+ driver.
That is not sufficiently clear. What does "risk of no power capping capability
working" mean, in particular?
intremap= [X86-64, Intel-IOMMU]
on enable Interrupt Remapping (default)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 1bb62ca..2654e13 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -866,6 +866,7 @@ static struct cpufreq_driver intel_pstate_driver = {
};
static int __initdata no_load;
+static unsigned int ora_force;
static int intel_pstate_msrs_not_valid(void)
{
@@ -1003,7 +1004,8 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
case PSS:
return intel_pstate_no_acpi_pss();
case PPC:
- return intel_pstate_has_acpi_ppc();
+ return intel_pstate_has_acpi_ppc() &&
+ (!ora_force);
}
}
@@ -1078,6 +1080,8 @@ static int __init intel_pstate_setup(char *str)
if (!strcmp(str, "disable"))
no_load = 1;
+ if (!strcmp(str, "ora_force"))
+ ora_force = 1;
return 0;
}
early_param("intel_pstate", intel_pstate_setup);
And can anyone please remind me what was wrong with a "force" option that would
work for everyone, not just Oracle/Sun?
That was my suggestion as well (i.e. a parameter to bypass the vendor
checks), but Linda didn't like it. My personal opinion is that unless
it's generic, I don't really feel like having a force option solely for
oracle. I'm not convinced you want this for production machines, and I
think for debug purposes I don't want a vendor specific param.
I am OK with a generic parameter.
Anyway I hope there is a parameter to allow us load intel_pstate on
Oracle boxes, specific to Oracle or generic.
Thanks,
Ethan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/