[RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length

[RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length

[Konstantin Ananyev]

That's an alternative way to fix the problem described in the patch:
http://dpdk.org/ml/archives/dev/2014-December/009394.html.
The main difference is:
- move buf_len fields out of rearm_data marker.
- make ixgbe_recv_pkts_vec() not touch buf_len field at all
(as all other RX functions behave).

Signed-off-by: Konstantin Ananyev <konstantin.ananyev-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 lib/librte_mbuf/rte_mbuf.h            |  7 +++++--
 lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 20 +++++++++++++++-----
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 2e5fce5..bb88318 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -179,6 +179,8 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask);
 typedef void    *MARKER[0];   /**< generic marker for a point in a structure */
 typedef uint64_t MARKER64[0]; /**< marker that allows us to overwrite 8 bytes
                                * with a single assignment */
+typedef uint8_t MARKER8[0];   /**< generic marker with 1B alignment */
+
 /**
  * The generic rte_mbuf, containing a packet mbuf.
  */
@@ -188,9 +190,10 @@ struct rte_mbuf {
 	void *buf_addr;           /**< Virtual address of segment buffer. */
 	phys_addr_t buf_physaddr; /**< Physical address of segment buffer. */
 
-	/* next 8 bytes are initialised on RX descriptor rearm */
-	MARKER64 rearm_data;
 	uint16_t buf_len;         /**< Length of segment buffer. */
+
+	/* next 6 bytes are initialised on RX descriptor rearm */
+	MARKER8 rearm_data;
 	uint16_t data_off;
 
 	/**
diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
index 579bc46..d5fc0cc 100644
--- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
+++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
@@ -79,13 +79,22 @@ ixgbe_rxq_rearm(struct igb_rx_queue *rxq)
 	/* Initialize the mbufs in vector, process 2 mbufs in one loop */
 	for (i = 0; i < RTE_IXGBE_RXQ_REARM_THRESH; i += 2, rxep += 2) {
 		__m128i vaddr0, vaddr1;
+		uintptr_t p0, p1;
 
 		mb0 = rxep[0].mbuf;
 		mb1 = rxep[1].mbuf;
 
-		/* flush mbuf with pkt template */
-		mb0->rearm_data[0] = rxq->mbuf_initializer;
-		mb1->rearm_data[0] = rxq->mbuf_initializer;
+		/*
+		 * Flush mbuf with pkt template.
+		 * Data to be rearmed is 6 bytes long.
+		 * Though, RX will overwrite ol_flags that are coming next
+		 * anyway. So overwrite whole 8 bytes with one load:
+		 * 6 bytes of rearm_data plus first 2 bytes of ol_flags.
+		 */
+		p0 = (uintptr_t)&mb0->rearm_data;
+		*(uint64_t *)p0 = rxq->mbuf_initializer;
+		p1 = (uintptr_t)&mb1->rearm_data;
+		*(uint64_t *)p1 = rxq->mbuf_initializer;
 
 		/* load buf_addr(lo 64bit) and buf_physaddr(hi 64bit) */
 		vaddr0 = _mm_loadu_si128((__m128i *)&(mb0->buf_addr));
@@ -732,14 +741,15 @@ static struct ixgbe_txq_ops vec_txq_ops = {
 int
 ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq)
 {
+	uintptr_t p;
 	struct rte_mbuf mb_def = { .buf_addr = 0 }; /* zeroed mbuf */
 
 	mb_def.nb_segs = 1;
 	mb_def.data_off = RTE_PKTMBUF_HEADROOM;
-	mb_def.buf_len = rxq->mb_pool->elt_size - sizeof(struct rte_mbuf);
 	mb_def.port = rxq->port_id;
 	rte_mbuf_refcnt_set(&mb_def, 1);
-	rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data);
+	p = (uintptr_t)&mb_def.rearm_data;
+	rxq->mbuf_initializer = *(uint64_t *)p;
 	return 0;
 }
 
-- 
1.8.3.1

Re: [RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length

[Jean-Mickael Guerin]

On 05/12/2014 16:20, Konstantin Ananyev wrote:
> That's an alternative way to fix the problem described in the patch:
> http://dpdk.org/ml/archives/dev/2014-December/009394.html.
> The main difference is:
> - move buf_len fields out of rearm_data marker.
> - make ixgbe_recv_pkts_vec() not touch buf_len field at all
> (as all other RX functions behave).
>
> Signed-off-by: Konstantin Ananyev <konstantin.ananyev-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> ---
>   lib/librte_mbuf/rte_mbuf.h            |  7 +++++--
>   lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 20 +++++++++++++++-----
>   2 files changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 2e5fce5..bb88318 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -179,6 +179,8 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask);
>   typedef void    *MARKER[0];   /**< generic marker for a point in a structure */
>   typedef uint64_t MARKER64[0]; /**< marker that allows us to overwrite 8 bytes
>                                  * with a single assignment */
> +typedef uint8_t MARKER8[0];   /**< generic marker with 1B alignment */
> +
>   /**
>    * The generic rte_mbuf, containing a packet mbuf.
>    */
> @@ -188,9 +190,10 @@ struct rte_mbuf {
>   	void *buf_addr;           /**< Virtual address of segment buffer. */
>   	phys_addr_t buf_physaddr; /**< Physical address of segment buffer. */
>
> -	/* next 8 bytes are initialised on RX descriptor rearm */
> -	MARKER64 rearm_data;
>   	uint16_t buf_len;         /**< Length of segment buffer. */
> +
> +	/* next 6 bytes are initialised on RX descriptor rearm */
> +	MARKER8 rearm_data;
>   	uint16_t data_off;
>
>   	/**
> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
> index 579bc46..d5fc0cc 100644
> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
> @@ -79,13 +79,22 @@ ixgbe_rxq_rearm(struct igb_rx_queue *rxq)
>   	/* Initialize the mbufs in vector, process 2 mbufs in one loop */
>   	for (i = 0; i < RTE_IXGBE_RXQ_REARM_THRESH; i += 2, rxep += 2) {
>   		__m128i vaddr0, vaddr1;
> +		uintptr_t p0, p1;
>
>   		mb0 = rxep[0].mbuf;
>   		mb1 = rxep[1].mbuf;
>
> -		/* flush mbuf with pkt template */
> -		mb0->rearm_data[0] = rxq->mbuf_initializer;
> -		mb1->rearm_data[0] = rxq->mbuf_initializer;
> +		/*
> +		 * Flush mbuf with pkt template.
> +		 * Data to be rearmed is 6 bytes long.
> +		 * Though, RX will overwrite ol_flags that are coming next
> +		 * anyway. So overwrite whole 8 bytes with one load:
> +		 * 6 bytes of rearm_data plus first 2 bytes of ol_flags.
> +		 */
> +		p0 = (uintptr_t)&mb0->rearm_data;
> +		*(uint64_t *)p0 = rxq->mbuf_initializer;
> +		p1 = (uintptr_t)&mb1->rearm_data;
> +		*(uint64_t *)p1 = rxq->mbuf_initializer;
>
>   		/* load buf_addr(lo 64bit) and buf_physaddr(hi 64bit) */
>   		vaddr0 = _mm_loadu_si128((__m128i *)&(mb0->buf_addr));
> @@ -732,14 +741,15 @@ static struct ixgbe_txq_ops vec_txq_ops = {
>   int
>   ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq)
>   {
> +	uintptr_t p;
>   	struct rte_mbuf mb_def = { .buf_addr = 0 }; /* zeroed mbuf */
>
>   	mb_def.nb_segs = 1;
>   	mb_def.data_off = RTE_PKTMBUF_HEADROOM;
> -	mb_def.buf_len = rxq->mb_pool->elt_size - sizeof(struct rte_mbuf);
>   	mb_def.port = rxq->port_id;
>   	rte_mbuf_refcnt_set(&mb_def, 1);
> -	rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data);
> +	p = (uintptr_t)&mb_def.rearm_data;
> +	rxq->mbuf_initializer = *(uint64_t *)p;
>   	return 0;
>   }
>
>

The patch introduces writes on unaligned data, but we can assume no 
performance penalty on intel hw, correct?

Re: [RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length

[Ananyev, Konstantin]

> -----Original Message-----
> From: Jean-Mickael Guerin [mailto:jean-mickael.guerin-pdR9zngts4EAvxtiuMwx3w@public.gmane.org]
> Sent: Friday, December 05, 2014 4:59 PM
> To: Ananyev, Konstantin
> Cc: dev-VfR2kkLFssw@public.gmane.org
> Subject: Re: [dpdk-dev] [RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length
> 
> On 05/12/2014 16:20, Konstantin Ananyev wrote:
> > That's an alternative way to fix the problem described in the patch:
> > http://dpdk.org/ml/archives/dev/2014-December/009394.html.
> > The main difference is:
> > - move buf_len fields out of rearm_data marker.
> > - make ixgbe_recv_pkts_vec() not touch buf_len field at all
> > (as all other RX functions behave).
> >
> > Signed-off-by: Konstantin Ananyev <konstantin.ananyev-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> > ---
> >   lib/librte_mbuf/rte_mbuf.h            |  7 +++++--
> >   lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 20 +++++++++++++++-----
> >   2 files changed, 20 insertions(+), 7 deletions(-)
> >
> > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> > index 2e5fce5..bb88318 100644
> > --- a/lib/librte_mbuf/rte_mbuf.h
> > +++ b/lib/librte_mbuf/rte_mbuf.h
> > @@ -179,6 +179,8 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask);
> >   typedef void    *MARKER[0];   /**< generic marker for a point in a structure */
> >   typedef uint64_t MARKER64[0]; /**< marker that allows us to overwrite 8 bytes
> >                                  * with a single assignment */
> > +typedef uint8_t MARKER8[0];   /**< generic marker with 1B alignment */
> > +
> >   /**
> >    * The generic rte_mbuf, containing a packet mbuf.
> >    */
> > @@ -188,9 +190,10 @@ struct rte_mbuf {
> >   	void *buf_addr;           /**< Virtual address of segment buffer. */
> >   	phys_addr_t buf_physaddr; /**< Physical address of segment buffer. */
> >
> > -	/* next 8 bytes are initialised on RX descriptor rearm */
> > -	MARKER64 rearm_data;
> >   	uint16_t buf_len;         /**< Length of segment buffer. */
> > +
> > +	/* next 6 bytes are initialised on RX descriptor rearm */
> > +	MARKER8 rearm_data;
> >   	uint16_t data_off;
> >
> >   	/**
> > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
> > index 579bc46..d5fc0cc 100644
> > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
> > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
> > @@ -79,13 +79,22 @@ ixgbe_rxq_rearm(struct igb_rx_queue *rxq)
> >   	/* Initialize the mbufs in vector, process 2 mbufs in one loop */
> >   	for (i = 0; i < RTE_IXGBE_RXQ_REARM_THRESH; i += 2, rxep += 2) {
> >   		__m128i vaddr0, vaddr1;
> > +		uintptr_t p0, p1;
> >
> >   		mb0 = rxep[0].mbuf;
> >   		mb1 = rxep[1].mbuf;
> >
> > -		/* flush mbuf with pkt template */
> > -		mb0->rearm_data[0] = rxq->mbuf_initializer;
> > -		mb1->rearm_data[0] = rxq->mbuf_initializer;
> > +		/*
> > +		 * Flush mbuf with pkt template.
> > +		 * Data to be rearmed is 6 bytes long.
> > +		 * Though, RX will overwrite ol_flags that are coming next
> > +		 * anyway. So overwrite whole 8 bytes with one load:
> > +		 * 6 bytes of rearm_data plus first 2 bytes of ol_flags.
> > +		 */
> > +		p0 = (uintptr_t)&mb0->rearm_data;
> > +		*(uint64_t *)p0 = rxq->mbuf_initializer;
> > +		p1 = (uintptr_t)&mb1->rearm_data;
> > +		*(uint64_t *)p1 = rxq->mbuf_initializer;
> >
> >   		/* load buf_addr(lo 64bit) and buf_physaddr(hi 64bit) */
> >   		vaddr0 = _mm_loadu_si128((__m128i *)&(mb0->buf_addr));
> > @@ -732,14 +741,15 @@ static struct ixgbe_txq_ops vec_txq_ops = {
> >   int
> >   ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq)
> >   {
> > +	uintptr_t p;
> >   	struct rte_mbuf mb_def = { .buf_addr = 0 }; /* zeroed mbuf */
> >
> >   	mb_def.nb_segs = 1;
> >   	mb_def.data_off = RTE_PKTMBUF_HEADROOM;
> > -	mb_def.buf_len = rxq->mb_pool->elt_size - sizeof(struct rte_mbuf);
> >   	mb_def.port = rxq->port_id;
> >   	rte_mbuf_refcnt_set(&mb_def, 1);
> > -	rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data);
> > +	p = (uintptr_t)&mb_def.rearm_data;
> > +	rxq->mbuf_initializer = *(uint64_t *)p;
> >   	return 0;
> >   }
> >
> >
> 
> The patch introduces writes on unaligned data, but we can assume no
> performance penalty on intel hw, correct?
> 

Yes to both:
it introduces 64bit unaligned store.
I run performance test on IVB board, didn't see any degradation.
Konstantin 

Re: [RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length

[Thomas Monjalon]

Konstantin,

It would be easier if you sent a v2 of the patchset from Jean-Mickael.
So, the first patch would be included with your rework of the second patch.
Please use --in-reply-to to make tracking from emails or archives easier.

Thanks
-- 
Thomas

Re: [RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length

[Jean-Mickael Guerin]

On 05/12/2014 18:07, Ananyev, Konstantin wrote:
>
>
>> -----Original Message-----
>> From: Jean-Mickael Guerin [mailto:jean-mickael.guerin-pdR9zngts4EAvxtiuMwx3w@public.gmane.org]
>> Sent: Friday, December 05, 2014 4:59 PM
>> To: Ananyev, Konstantin
>> Cc: dev-VfR2kkLFssw@public.gmane.org
>> Subject: Re: [dpdk-dev] [RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length
>>
>> On 05/12/2014 16:20, Konstantin Ananyev wrote:
>>> That's an alternative way to fix the problem described in the patch:
>>> http://dpdk.org/ml/archives/dev/2014-December/009394.html.
>>> The main difference is:
>>> - move buf_len fields out of rearm_data marker.
>>> - make ixgbe_recv_pkts_vec() not touch buf_len field at all
>>> (as all other RX functions behave).
>>>
>>> Signed-off-by: Konstantin Ananyev <konstantin.ananyev-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>>> ---
>>>    lib/librte_mbuf/rte_mbuf.h            |  7 +++++--
>>>    lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 20 +++++++++++++++-----
>>>    2 files changed, 20 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
>>> index 2e5fce5..bb88318 100644
>>> --- a/lib/librte_mbuf/rte_mbuf.h
>>> +++ b/lib/librte_mbuf/rte_mbuf.h
>>> @@ -179,6 +179,8 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask);
>>>    typedef void    *MARKER[0];   /**< generic marker for a point in a structure */
>>>    typedef uint64_t MARKER64[0]; /**< marker that allows us to overwrite 8 bytes
>>>                                   * with a single assignment */
>>> +typedef uint8_t MARKER8[0];   /**< generic marker with 1B alignment */
>>> +
>>>    /**
>>>     * The generic rte_mbuf, containing a packet mbuf.
>>>     */
>>> @@ -188,9 +190,10 @@ struct rte_mbuf {
>>>    	void *buf_addr;           /**< Virtual address of segment buffer. */
>>>    	phys_addr_t buf_physaddr; /**< Physical address of segment buffer. */
>>>
>>> -	/* next 8 bytes are initialised on RX descriptor rearm */
>>> -	MARKER64 rearm_data;
>>>    	uint16_t buf_len;         /**< Length of segment buffer. */
>>> +
>>> +	/* next 6 bytes are initialised on RX descriptor rearm */
>>> +	MARKER8 rearm_data;
>>>    	uint16_t data_off;
>>>
>>>    	/**
>>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
>>> index 579bc46..d5fc0cc 100644
>>> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
>>> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
>>> @@ -79,13 +79,22 @@ ixgbe_rxq_rearm(struct igb_rx_queue *rxq)
>>>    	/* Initialize the mbufs in vector, process 2 mbufs in one loop */
>>>    	for (i = 0; i < RTE_IXGBE_RXQ_REARM_THRESH; i += 2, rxep += 2) {
>>>    		__m128i vaddr0, vaddr1;
>>> +		uintptr_t p0, p1;
>>>
>>>    		mb0 = rxep[0].mbuf;
>>>    		mb1 = rxep[1].mbuf;
>>>
>>> -		/* flush mbuf with pkt template */
>>> -		mb0->rearm_data[0] = rxq->mbuf_initializer;
>>> -		mb1->rearm_data[0] = rxq->mbuf_initializer;
>>> +		/*
>>> +		 * Flush mbuf with pkt template.
>>> +		 * Data to be rearmed is 6 bytes long.
>>> +		 * Though, RX will overwrite ol_flags that are coming next
>>> +		 * anyway. So overwrite whole 8 bytes with one load:
>>> +		 * 6 bytes of rearm_data plus first 2 bytes of ol_flags.
>>> +		 */
>>> +		p0 = (uintptr_t)&mb0->rearm_data;
>>> +		*(uint64_t *)p0 = rxq->mbuf_initializer;
>>> +		p1 = (uintptr_t)&mb1->rearm_data;
>>> +		*(uint64_t *)p1 = rxq->mbuf_initializer;
>>>
>>>    		/* load buf_addr(lo 64bit) and buf_physaddr(hi 64bit) */
>>>    		vaddr0 = _mm_loadu_si128((__m128i *)&(mb0->buf_addr));
>>> @@ -732,14 +741,15 @@ static struct ixgbe_txq_ops vec_txq_ops = {
>>>    int
>>>    ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq)
>>>    {
>>> +	uintptr_t p;
>>>    	struct rte_mbuf mb_def = { .buf_addr = 0 }; /* zeroed mbuf */
>>>
>>>    	mb_def.nb_segs = 1;
>>>    	mb_def.data_off = RTE_PKTMBUF_HEADROOM;
>>> -	mb_def.buf_len = rxq->mb_pool->elt_size - sizeof(struct rte_mbuf);
>>>    	mb_def.port = rxq->port_id;
>>>    	rte_mbuf_refcnt_set(&mb_def, 1);
>>> -	rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data);
>>> +	p = (uintptr_t)&mb_def.rearm_data;
>>> +	rxq->mbuf_initializer = *(uint64_t *)p;
>>>    	return 0;
>>>    }
>>>
>>>
>>
>> The patch introduces writes on unaligned data, but we can assume no
>> performance penalty on intel hw, correct?
>>
>
> Yes to both:
> it introduces 64bit unaligned store.
> I run performance test on IVB board, didn't see any degradation.
> Konstantin
>
>
OK fine by me:

Acked-by: Jean-Mickael Guerin <jean-mickael.guerin-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>

Re: [RFC PATCH] ixgbe: ixgbe_recv_pkts_vec shouldn't override mbuf buffer length

[Thomas Monjalon]

2014-12-05 19:03, Jean-Mickael Guerin:
> On 05/12/2014 18:07, Ananyev, Konstantin wrote:
> > From: Jean-Mickael Guerin [mailto:jean-mickael.guerin-pdR9zngts4EAvxtiuMwx3w@public.gmane.org]
> >> On 05/12/2014 16:20, Konstantin Ananyev wrote:
> >>> That's an alternative way to fix the problem described in the patch:
> >>> http://dpdk.org/ml/archives/dev/2014-December/009394.html.
> >>> The main difference is:
> >>> - move buf_len fields out of rearm_data marker.
> >>> - make ixgbe_recv_pkts_vec() not touch buf_len field at all
> >>> (as all other RX functions behave).
> >>>
> >>> Signed-off-by: Konstantin Ananyev <konstantin.ananyev-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> >>
> >> The patch introduces writes on unaligned data, but we can assume no
> >> performance penalty on intel hw, correct?
> >
> > Yes to both:
> > it introduces 64bit unaligned store.
> > I run performance test on IVB board, didn't see any degradation.
> > Konstantin
> 
> OK fine by me:
> 
> Acked-by: Jean-Mickael Guerin <jean-mickael.guerin-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>

Applied, even if the patch is RFC, it will be validated as part of -rc3.

Thanks
-- 
Thomas