* [dpdk-dev] [PATCH] ixgbe: fix icc compile error
@ 2016-03-23 17:45 Ferruh Yigit
2016-03-23 19:35 ` Stephen Hemminger
0 siblings, 1 reply; 6+ messages in thread
From: Ferruh Yigit @ 2016-03-23 17:45 UTC (permalink / raw)
To: dev; +Cc: Ferruh Yigit
Fixes: 06554d381d97 ("ixgbe: speed up non-vector Tx")
icc (icc (ICC) 16.0.1 20151021) is generating following compile error:
"
CC ixgbe_rxtx.o
.../drivers/net/ixgbe/ixgbe_rxtx.c(153): error #3656: variable
"free" may be used before its value is set
(nb_free > 0 && m->pool != free[0]->pool)) {
^
"
Indeed this is a false positive and code is correct.
"nb_free" check prevents the free[] access before its value set.
But the patch is just for compiler to remove compiler error.
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
drivers/net/ixgbe/ixgbe_rxtx.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index ff6ddb8..ef1a26f 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -128,7 +128,8 @@ ixgbe_tx_free_bufs(struct ixgbe_tx_queue *txq)
struct ixgbe_tx_entry *txep;
uint32_t status;
int i, nb_free = 0;
- struct rte_mbuf *m, *free[RTE_IXGBE_TX_MAX_FREE_BUF_SZ];
+ struct rte_mbuf *m;
+ struct rte_mbuf *free[RTE_IXGBE_TX_MAX_FREE_BUF_SZ] = {0};
/* check DD bit on threshold descriptor */
status = txq->tx_ring[txq->tx_next_dd].wb.status;
--
2.5.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [dpdk-dev] [PATCH] ixgbe: fix icc compile error
2016-03-23 17:45 [dpdk-dev] [PATCH] ixgbe: fix icc compile error Ferruh Yigit
@ 2016-03-23 19:35 ` Stephen Hemminger
2016-03-23 21:26 ` Ferruh Yigit
0 siblings, 1 reply; 6+ messages in thread
From: Stephen Hemminger @ 2016-03-23 19:35 UTC (permalink / raw)
To: Ferruh Yigit; +Cc: dev
On Wed, 23 Mar 2016 17:45:58 +0000
Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> Fixes: 06554d381d97 ("ixgbe: speed up non-vector Tx")
>
> icc (icc (ICC) 16.0.1 20151021) is generating following compile error:
> "
> CC ixgbe_rxtx.o
> .../drivers/net/ixgbe/ixgbe_rxtx.c(153): error #3656: variable
> "free" may be used before its value is set
> (nb_free > 0 && m->pool != free[0]->pool)) {
> ^
> "
>
> Indeed this is a false positive and code is correct.
> "nb_free" check prevents the free[] access before its value set.
>
> But the patch is just for compiler to remove compiler error.
>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> drivers/net/ixgbe/ixgbe_rxtx.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
> index ff6ddb8..ef1a26f 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c
> @@ -128,7 +128,8 @@ ixgbe_tx_free_bufs(struct ixgbe_tx_queue *txq)
> struct ixgbe_tx_entry *txep;
> uint32_t status;
> int i, nb_free = 0;
> - struct rte_mbuf *m, *free[RTE_IXGBE_TX_MAX_FREE_BUF_SZ];
> + struct rte_mbuf *m;
> + struct rte_mbuf *free[RTE_IXGBE_TX_MAX_FREE_BUF_SZ] = {0};
>
> /* check DD bit on threshold descriptor */
> status = txq->tx_ring[txq->tx_next_dd].wb.status;
Although this fixes a compiler bug, it also introduces a performance hit.
The initialization will generate a string instruct (rep; stosz) and this
stalls the multi-execution unit on many Intel CPU's.
Better to add a override to the Makefile (for icc only and with big comment).
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [dpdk-dev] [PATCH] ixgbe: fix icc compile error
2016-03-23 19:35 ` Stephen Hemminger
@ 2016-03-23 21:26 ` Ferruh Yigit
2016-03-24 17:34 ` [dpdk-dev] [PATCH v2] ixgbe: disable icc compile warning Ferruh Yigit
0 siblings, 1 reply; 6+ messages in thread
From: Ferruh Yigit @ 2016-03-23 21:26 UTC (permalink / raw)
To: Stephen Hemminger; +Cc: dev
On 3/23/2016 7:35 PM, Stephen Hemminger wrote:
> On Wed, 23 Mar 2016 17:45:58 +0000
> Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>
>> Fixes: 06554d381d97 ("ixgbe: speed up non-vector Tx")
>>
>> icc (icc (ICC) 16.0.1 20151021) is generating following compile error:
>> "
>> CC ixgbe_rxtx.o
>> .../drivers/net/ixgbe/ixgbe_rxtx.c(153): error #3656: variable
>> "free" may be used before its value is set
>> (nb_free > 0 && m->pool != free[0]->pool)) {
>> ^
>> "
>>
>> Indeed this is a false positive and code is correct.
>> "nb_free" check prevents the free[] access before its value set.
>>
>> But the patch is just for compiler to remove compiler error.
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>> ---
>> drivers/net/ixgbe/ixgbe_rxtx.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
>> index ff6ddb8..ef1a26f 100644
>> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
>> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c
>> @@ -128,7 +128,8 @@ ixgbe_tx_free_bufs(struct ixgbe_tx_queue *txq)
>> struct ixgbe_tx_entry *txep;
>> uint32_t status;
>> int i, nb_free = 0;
>> - struct rte_mbuf *m, *free[RTE_IXGBE_TX_MAX_FREE_BUF_SZ];
>> + struct rte_mbuf *m;
>> + struct rte_mbuf *free[RTE_IXGBE_TX_MAX_FREE_BUF_SZ] = {0};
>>
>> /* check DD bit on threshold descriptor */
>> status = txq->tx_ring[txq->tx_next_dd].wb.status;
>
> Although this fixes a compiler bug, it also introduces a performance hit.
> The initialization will generate a string instruct (rep; stosz) and this
> stalls the multi-execution unit on many Intel CPU's.
>
> Better to add a override to the Makefile (for icc only and with big comment).
>
Thank you for the comment. Konstantin also expressed similar performance
concern related this patch.
Nack for the patch, we will look for different solution.
Regards,
ferruh
^ permalink raw reply [flat|nested] 6+ messages in thread
* [dpdk-dev] [PATCH v2] ixgbe: disable icc compile warning
2016-03-23 21:26 ` Ferruh Yigit
@ 2016-03-24 17:34 ` Ferruh Yigit
2016-03-24 17:47 ` Ananyev, Konstantin
0 siblings, 1 reply; 6+ messages in thread
From: Ferruh Yigit @ 2016-03-24 17:34 UTC (permalink / raw)
To: dev; +Cc: Stephen Hemminger, Konstantin Ananyev, Ferruh Yigit
icc (icc (ICC) 16.0.1 20151021) is generating following compile error:
"
CC ixgbe_rxtx.o
.../drivers/net/ixgbe/ixgbe_rxtx.c(153): error #3656: variable
"free" may be used before its value is set
(nb_free > 0 && m->pool != free[0]->pool)) {
^
"
Indeed this is a false positive and code is correct.
"nb_free" check prevents the free[] access before its value set.
Disabling this icc warning (#3656) for file ixgbe_rxtx.c.
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
drivers/net/ixgbe/Makefile | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/ixgbe/Makefile b/drivers/net/ixgbe/Makefile
index c032775..50bf51c 100644
--- a/drivers/net/ixgbe/Makefile
+++ b/drivers/net/ixgbe/Makefile
@@ -49,6 +49,8 @@ ifeq ($(CC), icc)
#
CFLAGS_BASE_DRIVER = -wd174 -wd593 -wd869 -wd981 -wd2259
+CFLAGS_ixgbe_rxtx.o += -wd3656
+
else ifeq ($(CC), clang)
#
# CFLAGS for clang
--
2.5.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [dpdk-dev] [PATCH v2] ixgbe: disable icc compile warning
2016-03-24 17:34 ` [dpdk-dev] [PATCH v2] ixgbe: disable icc compile warning Ferruh Yigit
@ 2016-03-24 17:47 ` Ananyev, Konstantin
2016-03-25 13:57 ` Bruce Richardson
0 siblings, 1 reply; 6+ messages in thread
From: Ananyev, Konstantin @ 2016-03-24 17:47 UTC (permalink / raw)
To: Yigit, Ferruh, dev; +Cc: Stephen Hemminger
> -----Original Message-----
> From: Yigit, Ferruh
> Sent: Thursday, March 24, 2016 5:35 PM
> To: dev@dpdk.org
> Cc: Stephen Hemminger; Ananyev, Konstantin; Yigit, Ferruh
> Subject: [PATCH v2] ixgbe: disable icc compile warning
>
> icc (icc (ICC) 16.0.1 20151021) is generating following compile error:
> "
> CC ixgbe_rxtx.o
> .../drivers/net/ixgbe/ixgbe_rxtx.c(153): error #3656: variable
> "free" may be used before its value is set
> (nb_free > 0 && m->pool != free[0]->pool)) {
> ^
> "
>
> Indeed this is a false positive and code is correct.
> "nb_free" check prevents the free[] access before its value set.
>
> Disabling this icc warning (#3656) for file ixgbe_rxtx.c.
>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> drivers/net/ixgbe/Makefile | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/ixgbe/Makefile b/drivers/net/ixgbe/Makefile
> index c032775..50bf51c 100644
> --- a/drivers/net/ixgbe/Makefile
> +++ b/drivers/net/ixgbe/Makefile
> @@ -49,6 +49,8 @@ ifeq ($(CC), icc)
> #
> CFLAGS_BASE_DRIVER = -wd174 -wd593 -wd869 -wd981 -wd2259
>
> +CFLAGS_ixgbe_rxtx.o += -wd3656
> +
> else ifeq ($(CC), clang)
> #
> # CFLAGS for clang
> --
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> 2.5.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [dpdk-dev] [PATCH v2] ixgbe: disable icc compile warning
2016-03-24 17:47 ` Ananyev, Konstantin
@ 2016-03-25 13:57 ` Bruce Richardson
0 siblings, 0 replies; 6+ messages in thread
From: Bruce Richardson @ 2016-03-25 13:57 UTC (permalink / raw)
To: Ananyev, Konstantin; +Cc: Yigit, Ferruh, dev, Stephen Hemminger
On Thu, Mar 24, 2016 at 05:47:21PM +0000, Ananyev, Konstantin wrote:
> > -----Original Message-----
> > From: Yigit, Ferruh
> > Sent: Thursday, March 24, 2016 5:35 PM
> > To: dev@dpdk.org
> > Cc: Stephen Hemminger; Ananyev, Konstantin; Yigit, Ferruh
> > Subject: [PATCH v2] ixgbe: disable icc compile warning
> >
> > icc (icc (ICC) 16.0.1 20151021) is generating following compile error:
> > "
> > CC ixgbe_rxtx.o
> > .../drivers/net/ixgbe/ixgbe_rxtx.c(153): error #3656: variable
> > "free" may be used before its value is set
> > (nb_free > 0 && m->pool != free[0]->pool)) {
> > ^
> > "
> >
> > Indeed this is a false positive and code is correct.
> > "nb_free" check prevents the free[] access before its value set.
> >
> > Disabling this icc warning (#3656) for file ixgbe_rxtx.c.
> >
> > Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> > ---
> > drivers/net/ixgbe/Makefile | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/net/ixgbe/Makefile b/drivers/net/ixgbe/Makefile
> > index c032775..50bf51c 100644
> > --- a/drivers/net/ixgbe/Makefile
> > +++ b/drivers/net/ixgbe/Makefile
> > @@ -49,6 +49,8 @@ ifeq ($(CC), icc)
> > #
> > CFLAGS_BASE_DRIVER = -wd174 -wd593 -wd869 -wd981 -wd2259
> >
> > +CFLAGS_ixgbe_rxtx.o += -wd3656
> > +
> > else ifeq ($(CC), clang)
> > #
> > # CFLAGS for clang
> > --
>
> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
>
Applied to dpdk-next-net/rel_16_04
/Bruce
^ permalink raw reply [flat|nested] 6+ messages in thread
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2016-03-23 17:45 [dpdk-dev] [PATCH] ixgbe: fix icc compile error Ferruh Yigit
2016-03-23 19:35 ` Stephen Hemminger
2016-03-23 21:26 ` Ferruh Yigit
2016-03-24 17:34 ` [dpdk-dev] [PATCH v2] ixgbe: disable icc compile warning Ferruh Yigit
2016-03-24 17:47 ` Ananyev, Konstantin
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