Re: [dpdk-dev] [PATCH v1 1/1] test/power: check cpuinfo cur freq before scaling cur freq

[Richael Zhuang <Richael.Zhuang@arm.com>]

> -----Original Message-----
> From: David Hunt <david.hunt@intel.com>
> Sent: Wednesday, July 14, 2021 5:15 PM
> To: Richael Zhuang <Richael.Zhuang@arm.com>; dev@dpdk.org
> Cc: zhiminx.huang@intel.com; stable@dpdk.org
> Subject: Re: [PATCH v1 1/1] test/power: check cpuinfo cur freq before scaling
> cur freq
> 
> 
> On 14/7/2021 9:44 AM, Richael Zhuang wrote:
> > For acpi_cpufreq and cppc_cpufreq, both cpuinfo_cur_freq and
> > scaling_cur_freq exist. For pstate, only scaling_cur_freq exists.
> > And value in scaling_cur_freq and cpuinfo_cur_freq may not be the
> > same. For acpi_cpufreq and cppc_cpufreq, we should check
> > cpuinfo_cur_freq. So here checking cpuinfo_cur_freq before
> > scaling_cur_freq to make sure it works for all cpufreq drivers.
> >
> > Fixes: ff6dfb8e492f ("test/power: fix CPU frequency check")
> > Cc: david.hunt@intel.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Richael Zhuang <richael.zhuang@arm.com>
> > ---
> >   app/test/test_power_cpufreq.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/app/test/test_power_cpufreq.c
> > b/app/test/test_power_cpufreq.c index b8fc53925c..f56abb6f86 100644
> > --- a/app/test/test_power_cpufreq.c
> > +++ b/app/test/test_power_cpufreq.c
> > @@ -62,13 +62,13 @@ check_cur_freq(unsigned int lcore_id, uint32_t idx,
> bool turbo)
> >   	int i;
> >
> >   	if (snprintf(fullpath, sizeof(fullpath),
> > -		TEST_POWER_SYSFILE_SCALING_FREQ, lcore_id) < 0) {
> > +		TEST_POWER_SYSFILE_CPUINFO_FREQ, lcore_id) < 0) {
> >   		return 0;
> >   	}
> >   	f = fopen(fullpath, "r");
> >   	if (f == NULL) {
> >   		if (snprintf(fullpath, sizeof(fullpath),
> > -			TEST_POWER_SYSFILE_CPUINFO_FREQ, lcore_id) < 0)
> {
> > +			TEST_POWER_SYSFILE_SCALING_FREQ, lcore_id) < 0)
> {
> >   			return 0;
> >   		}
> >   		f = fopen(fullpath, "r");
> 
> 
> Hi Richael, I don't think this patch fixes anything. If the scaling file is not
> available, it will then attempt to open the cpuinfo file.
> Changing the order does not address the underlying issue.
> 
> It looks like the test is failing in check_cur_req, which is only rounding for
> cppc driver. I think it also needs to round for the other drivers. I've just
> checked intel_pstate driver now, and it needs the rounding. I would think
> that acpi driver also needs it. I'll do a bit more investigation and see if I
> can  change to acpi and attempt to confirm that all drivers need the rounding.
> 
> Rgds,
> Dave.
> 
> 
Hi David,
For acpi_cpufreq and cppc_cpufreq, both two files exist. So with the current code, it will check the scaling_cur_freq. But I think for this two drivers, it should check cpuinfo_cur_freq but not scaling_cur_freq. From my system, for acpi cpufreq, the value in cpuinfo_cur_freq and scaling_cur_freq are not the same.  So if not changing the check sequence, the result is:
##########
RTE>>power_cpufreq_autotest
POWER: Env isn't set yet!
POWER: Attempting to initialise ACPI cpufreq power management...
POWER: Initialized successfully for lcore 2 power management
POWER: Power management of lcore 2 has exited from 'userspace' mode and been set back to the original
POWER: Lcore id 128 can not exceeds 127
POWER: Initialized successfully for lcore 2 power management
POWER: Power management of lcore 2 is in use
POWER: Invalid lcore ID
POWER: NULL buffer supplied
POWER: Buffer size is not enough
POWER: Invalid lcore ID
POWER: Power management of lcore 2 has exited from 'userspace' mode and been set back to the original
Test Failed
RTE>>quit
#############

But after changing the check sequence, the result is OK from my test:
######
RTE>>power_cpufreq_autotest
POWER: Env isn't set yet!
POWER: Attempting to initialise ACPI cpufreq power management...
POWER: Initialized successfully for lcore 2 power management
POWER: Power management of lcore 2 has exited from 'userspace' mode and been set back to the original
POWER: Lcore id 128 can not exceeds 127
POWER: Initialized successfully for lcore 2 power management
POWER: Power management of lcore 2 is in use
POWER: Invalid lcore ID
POWER: NULL buffer supplied
POWER: Buffer size is not enough
POWER: Invalid lcore ID
POWER: Invalid lcore ID
POWER: Invalid frequency index 64, which should be less than 3
POWER: Invalid frequency index 3, which should be less than 3
POWER: Failed to enable turbo on lcore 2
POWER: Invalid lcore ID
POWER: Invalid lcore ID
POWER: Invalid lcore ID
POWER: Invalid lcore ID
Turbo not available on lcore 2, skipping test
POWER: Power management of lcore 2 has exited from 'userspace' mode and been set back to the original
POWER: Power management of lcore 2 is not used
POWER: Lcore id 128 can not exceeds 127
Test OK
############