From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bsmtp5.bon.at (bsmtp5.bon.at [195.3.86.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10CD83A5459 for ; Fri, 10 Apr 2026 08:10:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.3.86.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775808621; cv=none; b=rVtSY2epRoE5tBMNuthSI6QzXrhz4hZ/KH74qLk3wLp9kVgflUEvv6IAtcB6SK7YMvZBUlbUZnEf/mkOn9vga7UYDlA0XhxqeA460nRXDWhirclNfBQN0Zmn6FjIvjjI0kzIbb0lo63OeOKDDS/E+FDuBLUxhcSUA+g+f9jyWwI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775808621; c=relaxed/simple; bh=UCmcaPxbF0sjIDtOzE3mZsXyzo0K6exunJlyZuxt+Yw=; h=Message-ID:Date:MIME-Version:Subject:To:References:From:Cc: In-Reply-To:Content-Type; b=Hsv5XgUHVjmlLZE+5lcMe/3QVX+8QhuEa2WlHls+Su4tM/NS+xuXLtZJlRByOr6tYgRIYTKjZSqHUgUzl2cCKiMFcU0wrmuTqxVAqX+y3IMu6MiWQBh83eihAVkZkjxtYBWzFdzEVCKaGl2OULRIvwGAqyXhQ0VlGqMMLwt2g9s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kdbg.org; spf=pass smtp.mailfrom=kdbg.org; arc=none smtp.client-ip=195.3.86.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kdbg.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kdbg.org Received: from bsmtp3.bon.at (unknown [192.168.181.101]) by bsmtp5.bon.at (Postfix) with ESMTPS id 4fsT9r4vzYz7S1YK for ; Fri, 10 Apr 2026 09:35:44 +0200 (CEST) Received: from [192.168.0.103] (unknown [93.83.142.38]) by bsmtp3.bon.at (Postfix) with ESMTPSA id 4fsT9f5FdXzRpLK; Fri, 10 Apr 2026 09:35:34 +0200 (CEST) Message-ID: <1b4c3562-8501-433e-afaf-2cb3a295b4ac@kdbg.org> Date: Fri, 10 Apr 2026 09:35:34 +0200 Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Git 2.54.0-rc1, subtests of t5310, t5326, t5327 To: Patrick Steinhardt References: <011701dcc767$8c2ab400$a4801c00$@nexbridge.com> <013301dcc774$5e9fffb0$1bdfff10$@nexbridge.com> <20260408173949.GB2850002@coredump.intra.peff.net> <014e01dcc793$8a9bab90$9fd302b0$@nexbridge.com> <016b01dcc79e$87472860$95d57920$@nexbridge.com> <20260408223233.GB2873736@coredump.intra.peff.net> Content-Language: en-US From: Johannes Sixt Cc: "brian m. carlson" , rsbecker@nexbridge.com, git@vger.kernel.org, Junio C Hamano , Jeff King In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Am 09.04.26 um 10:17 schrieb Patrick Steinhardt: > Yeah, agreed. I think we shouldn't make ourselves a hostage to platforms > that don't have reasonable support for writev(3p), as it does buy us > something on the majority of platforms that actually support it well. > > That of course doesn't mean that we shouldn't support such platforms. My take on this matter is that the use writev in Git's code gives POSIX centered contributors a false sense of security. POSIX's writev offers a number of guarantees that a compatibility implementation cannot provide. If uses of writev proliferate, I forsee the time when someone reports a problem on a compatibility platform, and one of us will point at POSIX and say "but that cannot happen because we have this and that guarantee". What did we gain with writev? There are half that many system calls. So what? Have there been any hard numbers about better performance, for example? Not even the call sites became simpler, see the commit that introduced the only caller: 26986f4cbaf3 ("sideband: use writev(3p) to send pktlines", 2026-03-13). -- Hannes