| Message ID | 1417703181-23093-2-git-send-email-jean-mickael.guerin@6wind.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers |
Return-Path: <dev-bounces@dpdk.org> X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [IPv6:::1]) by dpdk.org (Postfix) with ESMTP id 4754C8045; Thu, 4 Dec 2014 15:26:58 +0100 (CET) Received: from smtp-ft5.fr.colt.net (smtp-ft5.fr.colt.net [213.41.78.197]) by dpdk.org (Postfix) with ESMTP id 20F0C8043 for <dev@dpdk.org>; Thu, 4 Dec 2014 15:26:57 +0100 (CET) Received: from smtp-ex6.fr.colt.net (smtp-ex6.fr.colt.net [213.41.78.122]) by smtp-ft5.fr.colt.net (8.14.3/8.14.3/Debian-5+lenny1) with ESMTP id sB4EQvBj014869 for <dev@dpdk.org>; Thu, 4 Dec 2014 15:26:57 +0100 Received: from 33.106-14-84.ripe.coltfrance.com ([84.14.106.33] helo=proxy.6wind.com) by smtp-ex6.fr.colt.net with esmtp (Exim) (envelope-from <jean-mickael.guerin@6wind.com>) id 1XwXMv-0001x5-2G for <dev@dpdk.org>; Thu, 04 Dec 2014 15:26:57 +0100 Received: from 6wind.com (unknown [10.16.0.122]) by proxy.6wind.com (Postfix) with SMTP id 2072B5A038; Thu, 4 Dec 2014 15:26:55 +0100 (CET) Received: by 6wind.com (sSMTP sendmail emulation); Thu, 04 Dec 2014 15:26:55 +0100 From: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com> To: dev@dpdk.org Date: Thu, 4 Dec 2014 15:26:20 +0100 Message-Id: <1417703181-23093-2-git-send-email-jean-mickael.guerin@6wind.com> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1417703181-23093-1-git-send-email-jean-mickael.guerin@6wind.com> References: <1417703181-23093-1-git-send-email-jean-mickael.guerin@6wind.com> X-ACL-Warn: 1/1 recipients OK. Subject: [dpdk-dev] [PATCH 1/2] ixgbe: fix setup of mbuf initializer template X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> Errors-To: dev-bounces@dpdk.org Sender: "dev" <dev-bounces@dpdk.org> |
Commit Message
Jean-Mickael Guerin
Dec. 4, 2014, 2:26 p.m. UTC
Add a compiler barrier to make sure all fields covered by the marker rearm_data are assigned before the read. Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com> Acked-by: David Marchand <david.marchand@6wind.com> Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") --- lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 3 +++ 1 file changed, 3 insertions(+)
Comments
On Thu, Dec 04, 2014 at 03:26:20PM +0100, Jean-Mickael Guerin wrote: > Add a compiler barrier to make sure all fields covered by > the marker rearm_data are assigned before the read. > > Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com> > Acked-by: David Marchand <david.marchand@6wind.com> > Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") Acked-by: Bruce Richardson <bruce.richardson@intel.com> > --- > lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > index 579bc46..c1b5a78 100644 > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > @@ -739,6 +739,9 @@ ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) > 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); > + > + /* prevent compiler reordering: rearm_data covers previous fields */ > + rte_compiler_barrier(); > rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data); > return 0; > } > -- > 2.1.3 >
> -----Original Message----- > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson > Sent: Thursday, December 04, 2014 2:40 PM > To: Jean-Mickael Guerin > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH 1/2] ixgbe: fix setup of mbuf initializer template > > On Thu, Dec 04, 2014 at 03:26:20PM +0100, Jean-Mickael Guerin wrote: > > Add a compiler barrier to make sure all fields covered by > > the marker rearm_data are assigned before the read. > > > > Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com> > > Acked-by: David Marchand <david.marchand@6wind.com> > > Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") > > Acked-by: Bruce Richardson <bruce.richardson@intel.com> > > > --- > > lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > > index 579bc46..c1b5a78 100644 > > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > > @@ -739,6 +739,9 @@ ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) > > 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); > > + > > + /* prevent compiler reordering: rearm_data covers previous fields */ > > + rte_compiler_barrier(); > > rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data); > > return 0; > > } > > -- Hmm, can someone explain to me why do we need a compiler barrier here? Konstantin > > 2.1.3 > >
On 04/12/2014 15:42, Ananyev, Konstantin wrote: > > >> -----Original Message----- >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson >> Sent: Thursday, December 04, 2014 2:40 PM >> To: Jean-Mickael Guerin >> Cc: dev@dpdk.org >> Subject: Re: [dpdk-dev] [PATCH 1/2] ixgbe: fix setup of mbuf initializer template >> >> On Thu, Dec 04, 2014 at 03:26:20PM +0100, Jean-Mickael Guerin wrote: >>> Add a compiler barrier to make sure all fields covered by >>> the marker rearm_data are assigned before the read. >>> >>> Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com> >>> Acked-by: David Marchand <david.marchand@6wind.com> >>> Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") >> >> Acked-by: Bruce Richardson <bruce.richardson@intel.com> >> >>> --- >>> lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c >>> index 579bc46..c1b5a78 100644 >>> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c >>> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c >>> @@ -739,6 +739,9 @@ ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) >>> 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); >>> + >>> + /* prevent compiler reordering: rearm_data covers previous fields */ >>> + rte_compiler_barrier(); >>> rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data); >>> return 0; >>> } >>> -- > > Hmm, can someone explain to me why do we need a compiler barrier here? > Konstantin rearm_data is a separate field and as well an array of length zero, overlapping on purpose the fields data_off buf_len, port, refcnt. It might depend on compiler, but I could see a wrong value of 0UL for mbuf_initializer without the barrier (gcc 4.4.6). > >>> 2.1.3 >>>
> -----Original Message----- > From: Jean-Mickael Guerin [mailto:jean-mickael.guerin@6wind.com] > Sent: Thursday, December 04, 2014 3:15 PM > To: Ananyev, Konstantin; Richardson, Bruce > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH 1/2] ixgbe: fix setup of mbuf initializer template > > On 04/12/2014 15:42, Ananyev, Konstantin wrote: > > > > > >> -----Original Message----- > >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson > >> Sent: Thursday, December 04, 2014 2:40 PM > >> To: Jean-Mickael Guerin > >> Cc: dev@dpdk.org > >> Subject: Re: [dpdk-dev] [PATCH 1/2] ixgbe: fix setup of mbuf initializer template > >> > >> On Thu, Dec 04, 2014 at 03:26:20PM +0100, Jean-Mickael Guerin wrote: > >>> Add a compiler barrier to make sure all fields covered by > >>> the marker rearm_data are assigned before the read. > >>> > >>> Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com> > >>> Acked-by: David Marchand <david.marchand@6wind.com> > >>> Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") > >> > >> Acked-by: Bruce Richardson <bruce.richardson@intel.com> > >> > >>> --- > >>> lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 3 +++ > >>> 1 file changed, 3 insertions(+) > >>> > >>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > >>> index 579bc46..c1b5a78 100644 > >>> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > >>> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > >>> @@ -739,6 +739,9 @@ ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) > >>> 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); > >>> + > >>> + /* prevent compiler reordering: rearm_data covers previous fields */ > >>> + rte_compiler_barrier(); > >>> rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data); > >>> return 0; > >>> } > >>> -- > > > > Hmm, can someone explain to me why do we need a compiler barrier here? > > Konstantin > > rearm_data is a separate field and as well an array of length zero, > overlapping on purpose the fields data_off buf_len, port, refcnt. > It might depend on compiler, but I could see a wrong value of 0UL for > mbuf_initializer without the barrier (gcc 4.4.6). Ah ok then. Probably it is some sort of bug in old version of the gcc. > > > > > >>> 2.1.3 > >>>
> > Add a compiler barrier to make sure all fields covered by > > the marker rearm_data are assigned before the read. > > > > Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com> > > Acked-by: David Marchand <david.marchand@6wind.com> > > Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") > > Acked-by: Bruce Richardson <bruce.richardson@intel.com> Applied The patch 2/2 won't be applied because another alternative has been approved. Thanks
diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c index 579bc46..c1b5a78 100644 --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c @@ -739,6 +739,9 @@ ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) 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); + + /* prevent compiler reordering: rearm_data covers previous fields */ + rte_compiler_barrier(); rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data); return 0; }