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From: Thierry Herbelot <thierry.herbelot@6wind.com>
To: dev@dpdk.org
Cc: Thierry Herbelot <thierry.herbelot@6wind.com>,
	Thomas Monjalon <thomas@monjalon.net>,
	Devendra Singh Rawat <dsinghrawat@marvell.com>,
	Alok Prasad <palok@marvell.com>, Jerin Jacob <jerinj@marvell.com>,
	Olivier Matz <olivier.matz@6wind.com>,
	Edwin Brossette <edwin.brossette@6wind.com>,
	stable@dpdk.org
Subject: [PATCH] net/qede: reduce the optimization level
Date: Wed,  3 Sep 2025 13:32:52 +0200	[thread overview]
Message-ID: <20250903113252.2496087-1-thierry.herbelot@6wind.com> (raw)

The qede PMD stopped working under Ubuntu-24.04 (using gcc-13) when
compiled with -O3 (default level for all DPDK code). A bug is opened
for this issue (see Link).

A first workaround is to just disable all optimizations (-O0), which
restores packet Rx with Qlogic NICs. However, the performance impact
is not acceptable (around 50% drop).

A better compromise is to use -O1 for the qede PMD:
- there is some perf impact,
- but the PMD is working as expected (packets are correctly received).

When compiling with both -O2 and -O3 and gcc-13, there is no packet
reception when using the qede PMD. The root cause could be missing
'volatile' keywords or missing memory barriers in the qede PMD code.

Link: https://bugs.dpdk.org/show_bug.cgi?id=1379
Signed-off-by: Thierry Herbelot <thierry.herbelot@6wind.com>
---
 drivers/net/qede/base/meson.build | 1 +
 drivers/net/qede/meson.build      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/net/qede/base/meson.build b/drivers/net/qede/base/meson.build
index a6dad3ec7bcc..6c8800a3f48f 100644
--- a/drivers/net/qede/base/meson.build
+++ b/drivers/net/qede/base/meson.build
@@ -55,3 +55,4 @@ foreach flag: error_cflags
         base_cflags += flag
     endif
 endforeach
+base_cflags += '-O1'
diff --git a/drivers/net/qede/meson.build b/drivers/net/qede/meson.build
index e1b21d6ff5cd..3c2a5205732a 100644
--- a/drivers/net/qede/meson.build
+++ b/drivers/net/qede/meson.build
@@ -22,3 +22,4 @@ sources = files(
 if cc.has_argument('-Wno-format-nonliteral')
     cflags += '-Wno-format-nonliteral'
 endif
+cflags += '-O1'
-- 
2.39.2


                 reply	other threads:[~2025-09-03 11:33 UTC|newest]

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