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[77.37.180.76]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-59580405777sm4804870e87.91.2025.11.19.06.56.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Nov 2025 06:56:51 -0800 (PST) Date: Wed, 19 Nov 2025 17:56:48 +0300 From: Vadim Goncharov To: Minsoo Choo Cc: John Baldwin , arch@FreeBSD.org Subject: Re: Future of armv7 Message-ID: <20251119175648.37922d1e@nuclight.lan> In-Reply-To: References: <8aa378a1-94fb-4cb1-9bca-8e68eb8e0938@FreeBSD.org> X-Mailer: Claws Mail 3.21.0 (GTK+ 2.24.33; amd64-portbld-freebsd13.4) List-Id: Discussion related to FreeBSD architecture List-Archive: https://lists.freebsd.org/archives/freebsd-arch List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arch@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.70 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-0.999]; NEURAL_HAM_LONG(-1.00)[-0.999]; NEURAL_HAM_SHORT(-0.70)[-0.700]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20230601]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36:c]; MIME_GOOD(-0.10)[text/plain]; ARC_NA(0.00)[]; RCVD_TLS_LAST(0.00)[]; MIME_TRACE(0.00)[0:+]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; TO_DN_SOME(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; DKIM_TRACE(0.00)[gmail.com:+]; FROM_HAS_DN(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::12f:from]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; PREVIOUSLY_DELIVERED(0.00)[arch@freebsd.org]; RCVD_VIA_SMTP_AUTH(0.00)[]; MLMMJ_DEST(0.00)[arch@freebsd.org]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; FREEMAIL_ENVFROM(0.00)[gmail.com] X-Rspamd-Queue-Id: 4dBPhW6B4tz46WC On Tue, 18 Nov 2025 01:56:08 +0000 Minsoo Choo wrote: > - Maintaining at least one 32-bit platform makes porting FreeBSD to new > 32-bit platforms easier in future. > > Following is why I decided to vote towards the removal. > - Usage of armv7 hardwares have been quickly dwindling in the past few > years. Since I started studying in univeristy, the only armv7 I've seen is > ARM Cortex-M for old stm32 courses. Even including Cortex-M, I don't see > anyone around me who uses armv7 in their project or work. stable/15 will > give 3 more years of support for armv7, and I expect that people will use > armv7 dramatically less by then. > - Warner mentioned OOM issues. 32-bit architectures usually have maximum > memory capacity of 4GB, and introducing another 32-bit architecture won't > solve this problem (unless they come up with something like PAE, but why > would anyone come up with PAE if there are 64-bit architectures?). Thus, > claims like "maintain at least one 32-bit architecture for future 32-bit > architecture" don't really make sense to me. Even if we assume there will be > a revolutionary 32-bit platform that can replace all existing 64-bit > platforms under special circumstances, how do we know when the day will > come? People in this list have said that there might be a future 32-bit > platform, but I haven't heard what the plan is if there is NO such > architecture in future. How can we tell? When is the time to remove armv7 if > we really don't see another 32-bit alternative for decades? > - Cost of maintaining, testing, and releasing FreeBSD on these platforms. As > FreeBSD build system encompasses different architectures and operating > systems should abstract different hardwares, armv6 might affect code other > than its own architecture-specific code, such as jemalloc that Warner have > mentioned. OOM and compiling is not an issue when the system is just target. For example, in VM/clouds, even i386 images are used because they use less memory so you can buy more of them for same price. Another target is embedded/IoT world: while vast majority of constrained devices have less than dozen Kb of RAM (see IEEE 802.15.4/6LoWPAN world, C2 class by RFC 7228), situation may change towards 32-bits addressing in future when 32-bit may become more cheap than current 32-bit architectures. -- WBR, @nuclight