From: Stephen Hemminger <stephen@networkplumber.org>
To: Thierry Herbelot <thierry.herbelot@6wind.com>
Cc: dev@dpdk.org, 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: Re: [PATCH] net/qede: reduce the optimization level
Date: Fri, 5 Sep 2025 20:59:55 -0700 [thread overview]
Message-ID: <20250905205955.74b15b75@hermes.local> (raw)
In-Reply-To: <20250903113252.2496087-1-thierry.herbelot@6wind.com>
On Wed, 3 Sep 2025 13:32:52 +0200
Thierry Herbelot <thierry.herbelot@6wind.com> wrote:
> 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>
Since GCC 14 and 15 are available do they fix the problem?
If so, the the hack should be limited to Gcc 13 and with
more complete comment.
prev parent reply other threads:[~2025-09-06 4:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-03 11:32 Thierry Herbelot
2025-09-06 3:59 ` Stephen Hemminger [this message]
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