From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fout-b5-smtp.messagingengine.com (fout-b5-smtp.messagingengine.com [202.12.124.148]) (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 5106B18CC1C for ; Sun, 24 Nov 2024 23:58:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.12.124.148 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492683; cv=none; b=N48d/dbsem2Js7GpRlZcWoZpZetEXovBYpFEzjVfz3bZUB0Ef++UhkwrrPhdNYsxuElR5Qqgi8Cowm9DWSe9Gy170GUV/0jGJsbtIMargbtXwUJ2uY2QlODn5h6LZNoepndo46PsSqSkZZdqdOs/52KvMpAGaNElDFqbGbWP8bE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492683; c=relaxed/simple; bh=hdK9HvMPVHzbSEKx5fyFMHZdf0aRlEiu2PyKWJzmqSU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=KUpFKI6ZH02VDC6dGGmJCE1JW5yNsr2dA4S4pNFjYga9wzYSSkWWYfe9CvJKgeFnvTUD3rdVmbpYPvrr3iqj0gOLVc48cHf/WhwLimuDjmGKP36UT1n4JoA3Wv6vj3pNM/fi6cLQ8tLfFe+QU8lTp3sMMPuCkQNnmfca5EwyJLk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=pobox.com; spf=pass smtp.mailfrom=pobox.com; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=HuUXJqFB; arc=none smtp.client-ip=202.12.124.148 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=pobox.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pobox.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="HuUXJqFB" Received: from phl-compute-05.internal (phl-compute-05.phl.internal [10.202.2.45]) by mailfout.stl.internal (Postfix) with ESMTP id 13ECC114011C; Sun, 24 Nov 2024 18:58:00 -0500 (EST) Received: from phl-frontend-01 ([10.202.2.160]) by phl-compute-05.internal (MEProxy); Sun, 24 Nov 2024 18:58:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; t= 1732492679; x=1732579079; bh=/Z/CmqKkZTM/fgFZbPnxM/oGxXvigVU0lq8 PJZRn2To=; b=HuUXJqFBF4ou32j7Vo8Xq5Mr+4movff4UyQA7k9c/C1DRLG8pmN YH7yCqvzujVX884GzvuGLGVLIDxw8EQkjwzrbAy6nqxA3aGIQM7COnvHnNR09bIL 3i+fWlO/3QaJjSAQ5AP2gskF5PmfHIqiAM7WLXoyPwFeuk1SINrQ32cdYyySRfKS phRS2hJhaGX3H2mueLjOyAsT+pnDZ/fxBzdCD8LR3Uukcz6ULi4Rp3t9YR2RYSB6 dpP4JxGpEHFbNTRCC0U10uLyc2RmPZ9I5U3p9lAkVcA5uWsWBzDRvCynMEAbcYgX kZ+LWlofwmbZPgIAeNkJzB6eCJ2d4fVOcBg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefuddrgeeggdduiecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdpuffr tefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnth hsucdlqddutddtmdenucfjughrpefhvfevufgjfhffkfgfgggtsehttdertddtredtnecu hfhrohhmpefluhhnihhoucevucfjrghmrghnohcuoehgihhtshhtvghrsehpohgsohigrd gtohhmqeenucggtffrrghtthgvrhhnpeefveetteejheeugeffledvteeiveffueefjeel ueffteeigffgfedthfefieegieenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmh epmhgrihhlfhhrohhmpehgihhtshhtvghrsehpohgsohigrdgtohhmpdhnsggprhgtphht thhopeduuddpmhhouggvpehsmhhtphhouhhtpdhrtghpthhtohepshhtohhlvggvsehgmh grihhlrdgtohhmpdhrtghpthhtohepjhhonhgrthhhrghnthgrnhhmhiesghhoohhglhgv rdgtohhmpdhrtghpthhtohepghhithhgihhtghgrughgvghtsehgmhgrihhlrdgtohhmpd hrtghpthhtohepghhithesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehj ohhhrghnnhgvshdrshgthhhinhguvghlihhnsehgmhigrdguvgdprhgtphhtthhopehpvg hffhesphgvfhhfrdhnvghtpdhrtghpthhtohepphhssehpkhhsrdhimhdprhgtphhtthho pehmvgesthhtrgihlhhorhhrrdgtohhmpdhrtghpthhtohepjhhohhhntggrihekieesgh hmrghilhdrtghomh X-ME-Proxy: Feedback-ID: if26b431b:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 24 Nov 2024 18:57:59 -0500 (EST) From: Junio C Hamano To: Derrick Stolee Cc: Jonathan Tan , Derrick Stolee via GitGitGadget , git@vger.kernel.org, johannes.schindelin@gmx.de, peff@peff.net, ps@pks.im, me@ttaylorr.com, johncai86@gmail.com, newren@gmail.com Subject: Re: [PATCH 0/7] pack-objects: Create an alternative name hash algorithm (recreated) In-Reply-To: (Derrick Stolee's message of "Fri, 22 Nov 2024 10:27:19 -0500") References: <20241121235014.2554033-1-jonathantanmy@google.com> Date: Mon, 25 Nov 2024 08:57:57 +0900 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Derrick Stolee writes: >> (1) it hashes each path component separetely and rotates the whole >> thing only at a directory boundary. I'd imagine that this >> would make a big difference for languages that force overly >> long filenames at each level. > > I was confused by the "rotates the whole thing only at a directory > boundary" statement. Yeah, I guess it was confusing. What I meant was that the entire result is shifted down with new material from left to right, but unlike the original, the outer thing (i.e. what is given to the caller as the result) is shifted only at the directory boundary, so we are not as aggressive to lose early bits by shifting them down to the right, as we are not shifting as fast as before. > I think one way to say what you mean is > > Each path component is hashed similarly to the standard name-hash, > and parent path component hashes are contributed via XOR after a > down-shift of 6 bits per level. Yes.