From: David Lang <david@lang.hm>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Jonathan Nieder <jrnieder@gmail.com>,
"brian m. carlson" <sandals@crustytoothpaste.net>,
Git Mailing List <git@vger.kernel.org>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>,
demerphq <demerphq@gmail.com>,
agl@google.com, keccak@noekeon.org
Subject: Re: Hash algorithm analysis
Date: Mon, 11 Jun 2018 17:11:13 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.02.1806111708540.23278@nftneq.ynat.uz> (raw)
In-Reply-To: <878t7kx5t3.fsf@evledraar.gmail.com>
[-- Attachment #1: Type: TEXT/PLAIN, Size: 956 bytes --]
On Tue, 12 Jun 2018, Ævar Arnfjörð Bjarmason wrote:
>> From a performance standpoint, I have to say (once more) that crypto
>> performance actually mattered a lot less than I originally thought it
>> would. Yes, there are phases that do care, but they are rare.
>
> One real-world case is rebasing[1]. As noted in that E-Mail of mine a
> year ago we can use SHA1DC v.s. OpenSSL as a stand-in for the sort of
> performance difference we might expect between hash functions, although
> as you note this doesn't account for the difference in length.
when you are rebasing, how many hashes do you need to calculate? a few dozen, a
few hundred, a few thousand, a few hundered thousand?
If the common uses of rebasing are on the low end, then the fact that the hash
takes a bit longer won't matter much because the entire job is so fast.
And at the high end, I/O will probably dominate.
so where does it really make a human visible difference?
David Lang
next prev parent reply other threads:[~2018-06-12 0:11 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-09 20:56 State of NewHash work, future directions, and discussion brian m. carlson
2018-06-09 21:26 ` Ævar Arnfjörð Bjarmason
2018-06-09 22:49 ` Hash algorithm analysis brian m. carlson
2018-06-11 19:29 ` Jonathan Nieder
2018-06-11 20:20 ` Linus Torvalds
2018-06-11 23:27 ` Ævar Arnfjörð Bjarmason
2018-06-12 0:11 ` David Lang [this message]
2018-06-12 0:45 ` Linus Torvalds
2018-06-11 22:35 ` brian m. carlson
2018-06-12 16:21 ` Gilles Van Assche
2018-06-13 23:58 ` brian m. carlson
2018-06-15 10:33 ` Gilles Van Assche
2018-07-20 21:52 ` brian m. carlson
2018-07-21 0:31 ` Jonathan Nieder
2018-07-21 19:52 ` Ævar Arnfjörð Bjarmason
2018-07-21 20:25 ` brian m. carlson
2018-07-21 22:38 ` Johannes Schindelin
2018-07-21 23:09 ` Linus Torvalds
2018-07-21 23:59 ` brian m. carlson
2018-07-22 9:34 ` Eric Deplagne
2018-07-22 14:21 ` brian m. carlson
2018-07-22 14:55 ` Eric Deplagne
2018-07-26 10:05 ` Johannes Schindelin
2018-07-22 15:23 ` Joan Daemen
2018-07-22 18:54 ` Adam Langley
2018-07-26 10:31 ` Johannes Schindelin
2018-07-23 12:40 ` demerphq
2018-07-23 12:48 ` Sitaram Chamarty
2018-07-23 12:55 ` demerphq
2018-07-23 18:23 ` Linus Torvalds
2018-07-23 17:57 ` Stefan Beller
2018-07-23 18:35 ` Jonathan Nieder
2018-07-24 19:01 ` Edward Thomson
2018-07-24 20:31 ` Linus Torvalds
2018-07-24 20:49 ` Jonathan Nieder
2018-07-24 21:13 ` Junio C Hamano
2018-07-24 22:10 ` brian m. carlson
2018-07-30 9:06 ` Johannes Schindelin
2018-07-30 20:01 ` Dan Shumow
2018-08-03 2:57 ` Jonathan Nieder
2018-09-18 15:18 ` Joan Daemen
2018-09-18 15:32 ` Jonathan Nieder
2018-09-18 16:50 ` Linus Torvalds
2018-07-25 8:30 ` [PATCH 0/2] document that NewHash is now SHA-256 Ævar Arnfjörð Bjarmason
2018-07-25 8:30 ` [PATCH 1/2] doc hash-function-transition: note the lack of a changelog Ævar Arnfjörð Bjarmason
2018-07-25 8:30 ` [PATCH 2/2] doc hash-function-transition: pick SHA-256 as NewHash Ævar Arnfjörð Bjarmason
2018-07-25 16:45 ` Junio C Hamano
2018-07-25 17:25 ` Jonathan Nieder
2018-07-25 21:32 ` Junio C Hamano
2018-07-26 13:41 ` [PATCH v2 " Ævar Arnfjörð Bjarmason
2018-08-03 7:20 ` Jonathan Nieder
2018-08-03 16:40 ` Junio C Hamano
2018-08-03 17:01 ` Linus Torvalds
2018-08-03 16:42 ` Linus Torvalds
2018-08-03 17:43 ` Ævar Arnfjörð Bjarmason
2018-08-04 8:52 ` Jonathan Nieder
2018-08-03 17:45 ` brian m. carlson
2018-07-25 22:56 ` [PATCH " brian m. carlson
2018-06-11 21:19 ` Hash algorithm analysis Ævar Arnfjörð Bjarmason
2018-06-21 8:20 ` Johannes Schindelin
2018-06-21 22:39 ` brian m. carlson
2018-06-11 18:09 ` State of NewHash work, future directions, and discussion Duy Nguyen
2018-06-12 1:28 ` brian m. carlson
2018-06-11 19:01 ` Jonathan Nieder
2018-06-12 2:28 ` brian m. carlson
2018-06-12 2:42 ` Jonathan Nieder
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