On Oct 6, 2014, at 10:54 AM, Ananyev, Konstantin <konstantin.ananyev at intel.com> wrote:
>> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Bruce Richardson >> Sent: Monday, October 06, 2014 3:54 PM >> To: Wiles, Roger Keith (Wind River) >> Cc: dev at dpdk.org >> Subject: Re: [dpdk-dev] [PATCH 2/2] Adding the routines >> rte_pktmbuf_alloc_bulk() and rte_pktmbuf_free_bulk() >> >> On Mon, Oct 06, 2014 at 03:50:38PM +0100, Wiles, Roger Keith wrote: >>> Hi Bruce, >>> >>> Do I need to reject the for the new routines or just make sure the vector >>> driver does not get updated to use those routines? >>> >> >> The new routines are probably useful in the general case. I see no issue >> with having them in the code, so long as the vector driver is not modified >> to use them. > > I 'd say the same thing for non-vector RX/TX PMD code-paths too. > > BTW, are the new functions comments valid? > > + * @return > + * - 0 if the number of mbufs allocated was ok > + * - <0 is an ERROR. > + */ > +static inline int __rte_mbuf_raw_alloc_bulk( > > Though, as I can see __rte_mbuf_raw_alloc_bulk() returns either: > - number of allocated mbuf (cnt) > - negative error code Let me fix up the comments. > > And: > + * @return > + * - The number of valid mbufs pointers in the m_list array. > + * - Zero if the request cnt could not be allocated. > + */ > +static inline int __attribute__((always_inline)) > +rte_pktmbuf_alloc_bulk(struct rte_mempool *mp, struct rte_mbuf *m_list[], > int16_t cnt) > +{ > + return __rte_mbuf_raw_alloc_bulk(mp, m_list, cnt); > +} > > Shouldn't be "less than zero if the request cnt could not be allocated."? > > BTW, is there any point to have __rte_mbuf_raw_alloc_bulk() at all? > After all, as you are calling rte_pktmbuf_reset() inside it, it doesn't look > __raw__ any more. > Might be just put its content into rte_pktmbuf_alloc_bulk() and get rid of it. > I was just following the non-bulk routine style __rte_mbuf_raw_alloc(), but I can pull that into a single routine. > Also wonder, what is the advantage of having multiple counters inside the > same loop? > i.e: > + for(i = 0; i < cnt; i++) { > + m = *m_list++; > > Why not just: > > for(i = 0; i < cnt; i++) { > m = &m_list[i]; > > Same for free: > + while(npkts--) > + rte_pktmbuf_free(*m_list++); > > While not just: > for (i = 0; i < npkts; i++) > rte_pktmbuf_free(&m_list[i]); Maybe I have it wrong or the compilers are doing the right thing now, but at one point the &m_list[i] would cause the compiler to generate a shift or multiple of ?i? and then add it to the base of m_list. If that is not the case anymore then I can update the code as you suggested. Using the *m_list++ just adds the size of a pointer to a register and continues. > > Konstantin > >> >> /Bruce >> >>> Thanks >>> ++Keith >>> >>> On Oct 6, 2014, at 3:56 AM, Richardson, Bruce <bruce.richardson at >>> intel.com> wrote: >>> >>>> >>>> >>>>> -----Original Message----- >>>>> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Keith Wiles >>>>> Sent: Sunday, October 05, 2014 12:10 AM >>>>> To: dev at dpdk.org >>>>> Subject: [dpdk-dev] [PATCH 2/2] Adding the routines >>>>> rte_pktmbuf_alloc_bulk() >>>>> and rte_pktmbuf_free_bulk() >>>>> >>>>> Minor helper routines to mirror the mempool routines and remove the code >>>>> from applications. The ixgbe_rxtx_vec.c routine could be changed to use >>>>> the ret_pktmbuf_alloc_bulk() routine inplace of rte_mempool_get_bulk(). >>>>> >>>> >>>> I believe such a change would cause a performance regression, as the extra >>>> init code in the alloc_bulk() function would take >> additional cycles and is not needed. The vector routines use the mempool >> function directly, so that there is no overhead of mbuf >> initialization, as the vector routines use their additional "knowledge" of >> what the mbufs will be used for to init them in a faster manner >> than can be done inside the mbuf library. >>>> >>>> /Bruce >>>> >>>>> Signed-off-by: Keith Wiles <keith.wiles at windriver.com> >>>>> --- >>>>> lib/librte_mbuf/rte_mbuf.h | 77 >>>>> ++++++++++++++++++++++++++++++++++++++++++++++ >>>>> 1 file changed, 77 insertions(+) >>>>> >>>>> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h >>>>> index 1c6e115..f298621 100644 >>>>> --- a/lib/librte_mbuf/rte_mbuf.h >>>>> +++ b/lib/librte_mbuf/rte_mbuf.h >>>>> @@ -546,6 +546,41 @@ static inline void rte_pktmbuf_reset(struct rte_mbuf >>>>> *m) >>>>> } >>>>> >>>>> /** >>>>> + * @internal Allocate a list of mbufs from mempool *mp*. >>>>> + * The use of that function is reserved for RTE internal needs. >>>>> + * Please use rte_pktmbuf_alloc_bulk(). >>>>> + * >>>>> + * @param mp >>>>> + * The mempool from which mbuf is allocated. >>>>> + * @param m_list >>>>> + * The array to place the allocated rte_mbufs pointers. >>>>> + * @param cnt >>>>> + * The number of mbufs to allocate >>>>> + * @return >>>>> + * - 0 if the number of mbufs allocated was ok >>>>> + * - <0 is an ERROR. >>>>> + */ >>>>> +static inline int __rte_mbuf_raw_alloc_bulk(struct rte_mempool *mp, >>>>> struct >>>>> rte_mbuf *m_list[], int cnt) >>>>> +{ >>>>> + struct rte_mbuf *m; >>>>> + int ret; >>>>> + >>>>> + ret = rte_mempool_get_bulk(mp, (void **)m_list, cnt); >>>>> + if ( ret == 0 ) { >>>>> + int i; >>>>> + for(i = 0; i < cnt; i++) { >>>>> + m = *m_list++; >>>>> +#ifdef RTE_MBUF_REFCNT >>>>> + rte_mbuf_refcnt_set(m, 1); >>>>> +#endif /* RTE_MBUF_REFCNT */ >>>>> + rte_pktmbuf_reset(m); >>>>> + } >>>>> + ret = cnt; >>>>> + } >>>>> + return ret; >>>>> +} >>>>> + >>>>> +/** >>>>> * Allocate a new mbuf from a mempool. >>>>> * >>>>> * This new mbuf contains one segment, which has a length of 0. The pointer >>>>> @@ -671,6 +706,32 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m) >>>>> } >>>>> >>>>> /** >>>>> + * Allocate a list of mbufs from a mempool into a mbufs array. >>>>> + * >>>>> + * This mbuf list contains one segment per mbuf, which has a length of >>>>> 0. The >>>>> pointer >>>>> + * to data is initialized to have some bytes of headroom in the buffer >>>>> + * (if buffer size allows). >>>>> + * >>>>> + * The routine is just a simple wrapper routine to reduce code in the >>>>> application >>>>> and >>>>> + * provide a cleaner API for multiple mbuf requests. >>>>> + * >>>>> + * @param mp >>>>> + * The mempool from which the mbuf is allocated. >>>>> + * @param m_list >>>>> + * An array of mbuf pointers, cnt must be less then or equal to the >>>>> size of the >>>>> list. >>>>> + * @param cnt >>>>> + * Number of slots in the m_list array to fill. >>>>> + * @return >>>>> + * - The number of valid mbufs pointers in the m_list array. >>>>> + * - Zero if the request cnt could not be allocated. >>>>> + */ >>>>> +static inline int __attribute__((always_inline)) >>>>> +rte_pktmbuf_alloc_bulk(struct rte_mempool *mp, struct rte_mbuf *m_list[], >>>>> int16_t cnt) >>>>> +{ >>>>> + return __rte_mbuf_raw_alloc_bulk(mp, m_list, cnt); >>>>> +} >>>>> + >>>>> +/** >>>>> * Free a segment of a packet mbuf into its original mempool. >>>>> * >>>>> * Free an mbuf, without parsing other segments in case of chained >>>>> @@ -708,6 +769,22 @@ static inline void rte_pktmbuf_free(struct rte_mbuf >>>>> *m) >>>>> } >>>>> } >>>>> >>>>> +/** >>>>> + * Free a list of packet mbufs back into its original mempool. >>>>> + * >>>>> + * Free a list of mbufs by calling rte_pktmbuf_free() in a loop as a >>>>> wrapper >>>>> function. >>>>> + * >>>>> + * @param m_list >>>>> + * An array of rte_mbuf pointers to be freed. >>>>> + * @param npkts >>>>> + * Number of packets to free in list. >>>>> + */ >>>>> +static inline void rte_pktmbuf_free_bulk(struct rte_mbuf *m_list[], >>>>> int16_t >>>>> npkts) >>>>> +{ >>>>> + while(npkts--) >>>>> + rte_pktmbuf_free(*m_list++); >>>>> +} >>>>> + >>>>> #ifdef RTE_MBUF_REFCNT >>>>> >>>>> /** >>>>> -- >>>>> 2.1.0 >>>> >>> >>> Keith Wiles, Principal Technologist with CTO office, Wind River mobile >>> 972-213-5533 Keith Wiles, Principal Technologist with CTO office, Wind River mobile 972-213-5533
