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From: Stephen Hemminger <stephen@networkplumber.org>
To: Daniel Gregory <daniel.gregory@bytedance.com>
Cc: Ruifeng Wang <ruifeng.wang@arm.com>,
	dev@dpdk.org, Punit Agrawal <punit.agrawal@bytedance.com>,
	Liang Ma <liangma@bytedance.com>
Subject: Re: [PATCH] eal/arm: replace RTE_BUILD_BUG on non-constant
Date: Thu, 2 May 2024 11:27:53 -0700	[thread overview]
Message-ID: <20240502112753.1bdf08f7@hermes.local> (raw)
In-Reply-To: <20240502174420.GA3883350@ste-uk-lab-gw>

On Thu, 2 May 2024 18:44:20 +0100
Daniel Gregory <daniel.gregory@bytedance.com> wrote:

> What toolchain are you using? With your change I still get errors about
> the expression not being constant:
> 
> In file included from ../lib/eal/arm/include/rte_pause.h:13,
>                  from ../lib/eal/include/generic/rte_spinlock.h:25,
>                  from ../lib/eal/arm/include/rte_spinlock.h:17,
>                  from ../lib/telemetry/telemetry.c:20:
> ../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
> ../lib/eal/arm/include/rte_pause_64.h:156:23: error: expression in static assertion is not constant
> 156 |           static_assert(__builtin_constant_p(memorder), "memory order is not a constant");
>     |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> I'm cross-compiling with GCC v12.2 using the
> config/arm/arm64_armv8_linux_gcc cross-file, and enabling
> RTE_ARM_USE_WFE by uncommenting it in config/arm/meson.build and setting
> its value to true.


The problem with your patch is that checking at runtime generates additional
instructions in the critical path. Looks like more of a compiler bug.

  reply	other threads:[~2024-05-02 18:27 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-02 14:21 Daniel Gregory
2024-05-02 16:20 ` Stephen Hemminger
2024-05-02 17:44   ` Daniel Gregory
2024-05-02 18:27     ` Stephen Hemminger [this message]
2024-05-02 21:48     ` Stephen Hemminger
2024-05-03  9:46       ` Daniel Gregory
2024-05-04  0:56         ` Stephen Hemminger
2024-05-09 11:02           ` Daniel Gregory
2024-05-03 13:32 ` David Marchand
2024-05-03 14:21   ` Daniel Gregory
2024-05-03 18:27 ` [PATCH v2] " Daniel Gregory
2024-05-03 18:30   ` Daniel Gregory
2024-05-04  0:59   ` Stephen Hemminger
2024-05-06  9:30   ` Ruifeng Wang
2024-05-11 17:00   ` Wathsala Wathawana Vithanage
2024-05-04  1:02 ` [PATCH] " Stephen Hemminger
2024-05-09 11:11   ` Daniel Gregory
2024-05-09 16:47     ` Tyler Retzlaff
2024-05-11 16:48 ` Wathsala Wathawana Vithanage

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