Re: [PATCH v3] eal/x86: implement x86 specific tsc hz

[Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>]

On 02/10/2017 12:24, Jerin Jacob wrote:
> -----Original Message-----
>> Date: Mon, 2 Oct 2017 12:17:38 +0100
>> From: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
>> To: dev@dpdk.org
>> CC: harry.van.haaren@intel.com, bruce.richardson@intel.com
>> Subject: [dpdk-dev] [PATCH v3] eal/x86: implement x86 specific tsc hz
>> X-Mailer: git-send-email 2.9.5
>>
>> First, try to use CPUID Time Stamp Counter and Nominal Core Crystal
>> Clock Information Leaf to determine the tsc hz on platforms that
>> supports it (does not require privileged user).
>>
>> If the CPUID leaf is not available, then try to determine the tsc hz by
>> reading the MSR 0xCE (requires privileged user).
>>
>> Default to the tsc hz estimation if both methods fail.
>>
>> Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
>> Acked-by: Harry van Haaren <harry.van.haaren@intel.com>
>> Tested-by: Bruce Richardson <bruce.richardson@intel.com>
>> ---
>> DEPENDS on:
>> http://dpdk.org/dev/patchwork/patch/29086/
>>
>> v3:
>>   - acked-by and tested-by tags
>>
>> v2:
>>   - fix misspelled word in commit message
>>   - address comment for more clear code
>>
>>   lib/librte_eal/common/arch/x86/rte_cycles.c        | 142 +++++++++++++++++++++
>>   .../common/include/arch/x86/rte_cycles.h           |   7 +-
>>   lib/librte_eal/linuxapp/eal/Makefile               |   1 +
>>   3 files changed, 145 insertions(+), 5 deletions(-)
>>   create mode 100644 lib/librte_eal/common/arch/x86/rte_cycles.c
>> +
>> +static uint32_t
>> +check_model_wsm_nhm(uint8_t model)
>> +{
>> +	switch (model) {
>> +	/* Westmere */
>> +	case 0x25:
>> +	case 0x2C:
>> +	case 0x2F:
>> +	/* Nehalem */
>> +	case 0x1E:
>> +	case 0x1F:
>> +	case 0x1A:
> See next comment.
>
>> +	case 0x2E:
>> +		return 1;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static uint32_t
>> +check_model_gdm_dnv(uint8_t model)
>> +{
>> +	switch (model) {
>> +	/* Goldmont */
>> +	case 0x5C:
>> +	/* Denverton */
> Not adding "/* fall-through */" may break gcc 7 build.

See Bruce's comment on:
http://dpdk.org/ml/archives/dev/2017-September/074259.html

Thanks,
Sergio