DPDK patches and discussions
 help / color / mirror / Atom feed
From: WangDong <dong.wang.pro@hotmail.com>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH] librte_eal:Using compiler memory barrier for IA processor's rte_wmb/rte_rmb.
Date: Tue, 5 May 2015 23:38:27 +0800
Message-ID: <BLU436-SMTP1816B53EC78CA7DDCB12FAABFD10@phx.gbl> (raw)

The current implementation of rte_wmb/rte_rmb for x86 is using processor memory barrier. It's unnessary for IA processor, compiler memory barrier is enough. But if dpdk runing on a AMD processor, maybe we should use processor memory barrier.
I add a macro to distinguish them, if we compile DPDK for IA processor, add the macro (RTE_ARCH_X86_IA) can improve performance with compiler memory barrier. Or we can add RTE_ARCH_X86_AMD for using processor memory barrier, in this case, if didn't add the macro, the memory ordering will not be guaranteed. Which macro is better?
If this patch applied, the PMD's old implementation of compiler memory barrier (some volatile variable) can be fixed with rte_rmb() and rte_wmb() for any architecture.

 lib/librte_eal/common/include/arch/x86/rte_atomic.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic.h b/lib/librte_eal/common/include/arch/x86/rte_atomic.h
index e93e8ee..52b1e81 100644
--- a/lib/librte_eal/common/include/arch/x86/rte_atomic.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_atomic.h
@@ -49,10 +49,20 @@ extern "C" {
 #define	rte_mb() _mm_mfence()
+#ifdef RTE_ARCH_X86_IA
+#define rte_wmb() rte_compiler_barrier()
+#define rte_rmb() rte_compiler_barrier()
 #define	rte_wmb() _mm_sfence()
 #define	rte_rmb() _mm_lfence()
 /*------------------------- 16 bit atomic operations -------------------------*/

             reply	other threads:[~2015-05-05 15:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-05 15:38 WangDong [this message]
2015-05-05 22:46 ` Ananyev, Konstantin
2015-05-07 15:28   ` Wang Dong
2015-05-07 16:34     ` Ananyev, Konstantin
2015-05-09 10:24       ` Wang Dong
2015-05-11  9:59         ` Ananyev, Konstantin
2015-05-12 15:23           ` Wang Dong

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=BLU436-SMTP1816B53EC78CA7DDCB12FAABFD10@phx.gbl \
    --to=dong.wang.pro@hotmail.com \
    --cc=dev@dpdk.org \


* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:

AGPL code for this site: git clone https://public-inbox.org/public-inbox.git