From: "Wiles, Keith" <keith.wiles@intel.com>
To: Matan Azrad <matan@mellanox.com>
Cc: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>,
"jerin.jacob@caviumnetworks.com" <jerin.jacob@caviumnetworks.com>,
"Thomas Monjalon" <thomas@monjalon.net>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH 1/2] eal: add API to align integer to previous power of 2
Date: Sun, 18 Feb 2018 15:39:09 +0000 [thread overview]
Message-ID: <28F3DAA5-CCAB-4D2E-A6C9-FEB685A619C8@intel.com> (raw)
In-Reply-To: <AM4PR0501MB2657A5074F335C897F762008D2C90@AM4PR0501MB2657.eurprd05.prod.outlook.com>
> On Feb 18, 2018, at 12:11 AM, Matan Azrad <matan@mellanox.com> wrote:
>
> Hi Pavan
>
> Please see some comments below.
>
> From: Pavan Nikhilesh, Saturday, February 17, 2018 12:50 PM
>> Add 32b and 64b API's to align the given integer to the previous power of 2.
>>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
>> ---
>> lib/librte_eal/common/include/rte_common.h | 36
>> ++++++++++++++++++++++++++++++
>> 1 file changed, 36 insertions(+)
>>
>> diff --git a/lib/librte_eal/common/include/rte_common.h
>> b/lib/librte_eal/common/include/rte_common.h
>> index c7803e41c..126914f07 100644
>> --- a/lib/librte_eal/common/include/rte_common.h
>> +++ b/lib/librte_eal/common/include/rte_common.h
>> @@ -259,6 +259,24 @@ rte_align32pow2(uint32_t x)
>> return x + 1;
>> }
>>
>> +/**
>> + * Aligns input parameter to the previous power of 2
>> + *
>> + * @param x
>> + * The integer value to algin
>> + *
>> + * @return
>> + * Input parameter aligned to the previous power of 2
>
> I think the zero case(x=0) result should be documented.
>
>> + */
>> +static inline uint32_t
>> +rte_align32lowpow2(uint32_t x)
>
> What do you think about " rte_align32prevpow2"?
>
>> +{
>> + x = rte_align32pow2(x);
>
> In case of x is power of 2 number(already aligned), looks like the result here is x and the final result is (x >> 1)?
> Is it as you expect?
>
>> + x--;
>> +
>> + return x - (x >> 1);
>
> Why can't the implementation just be:
> return rte_align32pow2(x) >> 1;
>
> If the above is correct, Are you sure we need this API?
>
>> +}
>> +
>> /**
>> * Aligns 64b input parameter to the next power of 2
>> *
>> @@ -282,6 +300,24 @@ rte_align64pow2(uint64_t v)
>> return v + 1;
>> }
>>
>> +/**
>> + * Aligns 64b input parameter to the previous power of 2
>> + *
>> + * @param v
>> + * The 64b value to align
>> + *
>> + * @return
>> + * Input parameter aligned to the previous power of 2
>> + */
>> +static inline uint64_t
>> +rte_align64lowpow2(uint64_t v)
>> +{
>> + v = rte_align64pow2(v);
>> + v--;
>> +
>> + return v - (v >> 1);
>> +}
>> +
>
> Same comments for 64b API.
>
>> /*********** Macros for calculating min and max **********/
>>
>> /**
>> --
>> 2.16.1
>
>
> If it is a new API, I think it should be added to the map file and to be tagged as experimental. No?
>
Is this the type of API that needs to be marked experimental, we should be able to prove these functions, correct?
> Matan
Regards,
Keith
next prev parent reply other threads:[~2018-02-18 15:39 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-17 10:49 Pavan Nikhilesh
2018-02-17 10:49 ` [dpdk-dev] [PATCH 2/2] test: update common auto test Pavan Nikhilesh
2018-02-18 6:11 ` [dpdk-dev] [PATCH 1/2] eal: add API to align integer to previous power of 2 Matan Azrad
2018-02-18 15:39 ` Wiles, Keith [this message]
2018-02-19 6:03 ` Matan Azrad
2018-02-19 13:55 ` Wiles, Keith
2018-02-19 14:13 ` Matan Azrad
2018-02-19 14:21 ` Wiles, Keith
2018-02-19 16:18 ` Thomas Monjalon
2018-02-19 8:36 ` Pavan Nikhilesh
2018-02-19 11:36 ` [dpdk-dev] [PATCH v2 " Pavan Nikhilesh
2018-02-19 11:36 ` [dpdk-dev] [PATCH v2 2/2] test: update common auto test Pavan Nikhilesh
2018-02-19 12:09 ` [dpdk-dev] [PATCH v2 1/2] eal: add API to align integer to previous power of 2 Matan Azrad
2018-02-26 19:10 ` Pavan Nikhilesh
2018-02-27 19:30 ` Matan Azrad
2018-04-04 10:16 ` [dpdk-dev] [PATCH v3 " Pavan Nikhilesh
2018-04-04 10:16 ` [dpdk-dev] [PATCH v3 2/2] test: update common auto test Pavan Nikhilesh
2018-04-04 12:49 ` Thomas Monjalon
2018-04-04 12:54 ` Pavan Nikhilesh
2018-04-04 16:10 ` [dpdk-dev] [PATCH v3 1/2] eal: add API to align integer to previous power of 2 Matan Azrad
2018-04-04 16:42 ` Pavan Nikhilesh
2018-04-04 17:11 ` Matan Azrad
2018-04-04 17:51 ` Pavan Nikhilesh
2018-04-04 18:10 ` Matan Azrad
2018-04-04 18:15 ` Pavan Nikhilesh
2018-04-04 18:23 ` Matan Azrad
2018-04-04 18:36 ` Pavan Nikhilesh
2018-04-04 19:41 ` Matan Azrad
2018-04-04 13:20 ` [dpdk-dev] [PATCH v4] " Pavan Nikhilesh
2018-04-04 15:23 ` Thomas Monjalon
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