From: "Wang, Wei W" <wei.w.wang@intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: "andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH v4 10/11] x86/intel_pstate: support the use of intel_pstate in pmstat.c
Date: Wed, 9 Sep 2015 08:49:51 +0000 [thread overview]
Message-ID: <286AC319A985734F985F78AFA26841F7A2441E@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <55F00A7C02000078000A1231@prv-mh.provo.novell.com>
On 09/09/2015 16:32, Jan Beulich wrote:
>>> On 09.09.15 at 10:11, <wei.w.wang@intel.com> wrote:
> On 24/07/2015 22:16, Jan Beulich wrote:
>>>> On 25.06.15 at 13:17, <wei.w.wang@intel.com> wrote:
>> --- a/xen/drivers/acpi/pmstat.c
>> +++ b/xen/drivers/acpi/pmstat.c
>> --- a/xen/include/public/sysctl.h
>> +++ b/xen/include/public/sysctl.h
>> @@ -315,8 +315,18 @@ struct xen_get_cpufreq_para {
>> uint32_t scaling_cur_freq;
>>
>> char scaling_governor[CPUFREQ_NAME_LEN];
>> - uint32_t scaling_max_freq;
>> - uint32_t scaling_min_freq;
>> +
>> + union {
>> + uint32_t freq;
>> + uint32_t pct;
>> + } scaling_max;
>> +
>> + union {
>> + uint32_t freq;
>> + uint32_t pct;
>> + } scaling_min;
>
>>scaling_min and scaling_max should really be of the same type, so that
> someone wanting to introduce helper functions
>>or pointers to them can hand both interchangeably.
>
>>Also I'm starting to get tired of repeating that it is still unclear
>>how a
> consumer of the structure will know which of the
>>two fields of the unions are applicable.
>
>> Probably we don't need a union here. I plan to simply change them to
>> uint32_t scaling_max_perf; uint32_t scaling_max_perf;
>
>> Then it's up to the driver to put what kind of value to it. It's like
>> we simply provide a drinking vessel, and it depends on the user to put
>> water or milk into it. In our case, the intel_pstate driver assigns a
>> percentage vale to it (in the "uint32_t" type), and the legacy driver
>> assigns the absolute value to it (in the "uint32_t" type, too).
>I don't see how this will solve the problem of the consumer not knowing what kind of value it has to deal with.
The consumer is inside the print_cpufreq_para() function. I have put the code below:
+ if (!strncmp(p_cpufreq->scaling_driver,
+ "intel_pstate", CPUFREQ_NAME_LEN) )
+ {
+ printf("max_perf_pct : %d\n", p_cpufreq->scaling_max.pct);
+ printf("min_perf_pct : %d\n", p_cpufreq->scaling_min.pct);
+ printf("turbo_pct : %d\n", p_cpufreq->scaling_turbo_pct);
+ }
+ else
+ {
+ printf("scaling_avail_freq :");
+ for ( i = 0; i < p_cpufreq->freq_num; i++ )
+ if ( p_cpufreq->scaling_available_frequencies[i] ==
+ p_cpufreq->scaling_cur_freq )
+ printf(" *%d", p_cpufreq->scaling_available_frequencies[i]);
+ else
+ printf(" %d", p_cpufreq->scaling_available_frequencies[i]);
+ printf("\n");
+ printf("scaling frequency : max [%u] min [%u] cur [%u]\n",
+ p_cpufreq->scaling_max.freq,
+ p_cpufreq->scaling_min.freq,
+ p_cpufreq->scaling_cur_freq);
"p_cpufreq->scaling_driver" is the flag which distinguishes the usage of this "scaling_max_perf" field.
Best,
Wei
next prev parent reply other threads:[~2015-09-09 8:49 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-25 11:17 [PATCH v4 10/11] x86/intel_pstate: support the use of intel_pstate in pmstat.c Wei Wang
2015-07-24 14:15 ` Jan Beulich
2015-09-09 8:11 ` Wang, Wei W
2015-09-09 8:31 ` Jan Beulich
2015-09-09 8:49 ` Wang, Wei W [this message]
2015-09-09 9:00 ` Jan Beulich
2015-09-09 9:35 ` Wang, Wei W
2015-09-09 10:09 ` Jan Beulich
2015-09-09 10:35 ` Wang, Wei W
2015-09-09 11:57 ` Jan Beulich
2015-09-09 12:56 ` Wang, Wei W
2015-09-09 13:12 ` Jan Beulich
2015-09-09 15:16 ` Wang, Wei W
2015-09-09 15:55 ` Jan Beulich
2015-09-10 5:35 ` Wang, Wei W
2015-09-10 8:16 ` Jan Beulich
2015-09-10 9:33 ` Wang, Wei W
2015-09-10 9:55 ` Jan Beulich
2015-09-10 10:10 ` Wang, Wei W
2015-09-10 10:20 ` Jan Beulich
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