From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755895AbbIYLmj (ORCPT ); Fri, 25 Sep 2015 07:42:39 -0400 Received: from mail-ig0-f171.google.com ([209.85.213.171]:38401 "EHLO mail-ig0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753500AbbIYLmh (ORCPT ); Fri, 25 Sep 2015 07:42:37 -0400 Subject: Re: [PATCH 1/3] Make /dev/urandom scalable To: "Theodore Ts'o" , Jeff Epler , Andi Kleen , linux-kernel@vger.kernel.org, kirill.shutemov@linux.intel.com, herbert@gondor.apana.org.au, Andi Kleen References: <1442963767-14945-1-git-send-email-andi@firstfloor.org> <5603004A.20801@gmail.com> <20150923232841.GK1747@two.firstfloor.org> <5603E083.8020004@gmail.com> <20150924131235.GB6841@thunk.org> <56041E2C.2030602@gmail.com> <20150924165204.GA2835@unpythonic.net> <56044ADB.5050102@gmail.com> <20150924201413.GA3989@thunk.org> From: Austin S Hemmelgarn Message-ID: <560532FC.1070601@gmail.com> Date: Fri, 25 Sep 2015 07:41:48 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150924201413.GA3989@thunk.org> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms080901040002000901000806" X-Antivirus: avast! (VPS 150924-1, 2015-09-24), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a cryptographically signed message in MIME format. --------------ms080901040002000901000806 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-09-24 16:14, Theodore Ts'o wrote: > On Thu, Sep 24, 2015 at 03:11:23PM -0400, Austin S Hemmelgarn wrote: >>> That is a startling result. Please say what architecture, kernel >>> version, dieharder version and commandline arguments you are using to= >>> get 10% WEAK or FAILED assessments from dieharder on /dev/urandom. >> >> I do not remember what exact dieharder version or command-line argumen= ts >> (this was almost a decade ago), except that I compiled it from source >> myself, I do remember it was a 32-bit x86 processor (as that was sadly= all I >> had to run Linux on at the time), and an early 2.6 series kernel (whic= h if I >> remember correctly was already EOL by the time I was using it). > > It might have been nice if you had said this from the beginning > instead of making an unqualified statement with the assumption that it > was applicable to kernels likely to be used today in non-obsolete > systems. Otherwise it risks generating a click-bait article on > Phoronix that would get people really worried for no good reason... I sincerely apologize about this, I should have been more specific right = from the beginning (I need to get better about that when talking to=20 people, I'm so used to dealing with some of my friends who couldn't=20 event tell you the difference between RAM and a hard drive, think a bus=20 is only something you use for transportation, and get confused when I=20 try to properly explain even relatively simple CS and statistics concepts= ). > > There was a bug a long, long time ago (which where we weren't doing > sufficient locking and if two processes raced reading from > /dev/urandom at the same time, it was possible that the two processes > would get the same value read out from /dev/urandom). This was fixed > a long time ago, though, and in fact the scalability problem which > Andi is trying to fix was caused by that extra locking that was added. = :-) > > It's possible that is what you saw. I don't know, since there was no > reproduction information to back up your rather startling claim. I don't think this was what I hit, I'm pretty sure I had serialized the=20 dieharder runs. > > If you can reproduce consistent Dieharder failures, please do let us > know with detailed reproduction instructures. Will do. > > Many thanks, > > - Ted > --------------ms080901040002000901000806 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgMFADCABgkqhkiG9w0BBwEAAKCC Brgwgga0MIIEnKADAgECAgMRLfgwDQYJKoZIhvcNAQENBQAweTEQMA4GA1UEChMHUm9vdCBD QTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNp Z25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcwHhcN MTUwOTIxMTEzNTEzWhcNMTYwMzE5MTEzNTEzWjBjMRgwFgYDVQQDEw9DQWNlcnQgV29UIFVz ZXIxIzAhBgkqhkiG9w0BCQEWFGFoZmVycm9pbjdAZ21haWwuY29tMSIwIAYJKoZIhvcNAQkB FhNhaGVtbWVsZ0BvaGlvZ3QuY29tMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEA nQ/81tq0QBQi5w316VsVNfjg6kVVIMx760TuwA1MUaNQgQ3NyUl+UyFtjhpkNwwChjgAqfGd LIMTHAdObcwGfzO5uI2o1a8MHVQna8FRsU3QGouysIOGQlX8jFYXMKPEdnlt0GoQcd+BtESr pivbGWUEkPs1CwM6WOrs+09bAJP3qzKIr0VxervFrzrC5Dg9Rf18r9WXHElBuWHg4GYHNJ2V Ab8iKc10h44FnqxZK8RDN8ts/xX93i9bIBmHnFfyNRfiOUtNVeynJbf6kVtdHP+CRBkXCNRZ qyQT7gbTGD24P92PS2UTmDfplSBcWcTn65o3xWfesbf02jF6PL3BCrVnDRI4RgYxG3zFBJuG qvMoEODLhHKSXPAyQhwZINigZNdw5G1NqjXqUw+lIqdQvoPijK9J3eijiakh9u2bjWOMaleI SMRR6XsdM2O5qun1dqOrCgRkM0XSNtBQ2JjY7CycIx+qifJWsRaYWZz0aQU4ZrtAI7gVhO9h pyNaAGjvm7PdjEBiXq57e4QcgpwzvNlv8pG1c/hnt0msfDWNJtl3b6elhQ2Pz4w/QnWifZ8E BrFEmjeeJa2dqjE3giPVWrsH+lOvQQONsYJOuVb8b0zao4vrWeGmW2q2e3pdv0Axzm/60cJQ haZUv8+JdX9ZzqxOm5w5eUQSclt84u+D+hsCAwEAAaOCAVkwggFVMAwGA1UdEwEB/wQCMAAw VgYJYIZIAYb4QgENBEkWR1RvIGdldCB5b3VyIG93biBjZXJ0aWZpY2F0ZSBmb3IgRlJFRSBo ZWFkIG92ZXIgdG8gaHR0cDovL3d3dy5DQWNlcnQub3JnMA4GA1UdDwEB/wQEAwIDqDBABgNV HSUEOTA3BggrBgEFBQcDBAYIKwYBBQUHAwIGCisGAQQBgjcKAwQGCisGAQQBgjcKAwMGCWCG SAGG+EIEATAyBggrBgEFBQcBAQQmMCQwIgYIKwYBBQUHMAGGFmh0dHA6Ly9vY3NwLmNhY2Vy dC5vcmcwMQYDVR0fBCowKDAmoCSgIoYgaHR0cDovL2NybC5jYWNlcnQub3JnL3Jldm9rZS5j cmwwNAYDVR0RBC0wK4EUYWhmZXJyb2luN0BnbWFpbC5jb22BE2FoZW1tZWxnQG9oaW9ndC5j b20wDQYJKoZIhvcNAQENBQADggIBADMnxtSLiIunh/TQcjnRdf63yf2D8jMtYUm4yDoCF++J jCXbPQBGrpCEHztlNSGIkF3PH7ohKZvlqF4XePWxpY9dkr/pNyCF1PRkwxUURqvuHXbu8Lwn 8D3U2HeOEU3KmrfEo65DcbanJCMTTW7+mU9lZICPP7ZA9/zB+L0Gm1UNFZ6AU50N/86vjQfY WgkCd6dZD4rQ5y8L+d/lRbJW7ZGEQw1bSFVTRpkxxDTOwXH4/GpQfnfqTAtQuJ1CsKT12e+H NSD/RUWGTr289dA3P4nunBlz7qfvKamxPymHeBEUcuICKkL9/OZrnuYnGROFwcdvfjGE5iLB kjp/ttrY4aaVW5EsLASNgiRmA6mbgEAMlw3RwVx0sVelbiIAJg9Twzk4Ct6U9uBKiJ8S0sS2 8RCSyTmCRhJs0vvva5W9QUFGmp5kyFQEoSfBRJlbZfGX2ehI2Hi3U2/PMUm2ONuQG1E+a0AP u7I0NJc/Xil7rqR0gdbfkbWp0a+8dAvaM6J00aIcNo+HkcQkUgtfrw+C2Oyl3q8IjivGXZqT 5UdGUb2KujLjqjG91Dun3/RJ/qgQlotH7WkVBs7YJVTCxfkdN36rToPcnMYOI30FWa0Q06gn F6gUv9/mo6riv3A5bem/BdbgaJoPnWQD9D8wSyci9G4LKC+HQAMdLmGoeZfpJzKHMYIE0TCC BM0CAQEwgYAweTEQMA4GA1UEChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNl cnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcN AQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DANBglghkgBZQMEAgMFAKCCAiEwGAYJKoZI hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUwOTI1MTE0MTQ4WjBPBgkq hkiG9w0BCQQxQgRAe4sjJGNsE96UWOlDBeaKAIehyW1Rlzs2OWiAuiPk/5Oq7hTDunwDm8+6 ANaJE0yfo4Tu9IX0nNYYCl8/J4iM1TBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxEt+DCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DAN BgkqhkiG9w0BAQEFAASCAgCL2s8bYoao4/f115713NPBK6cRB2c6KTO84C/yCcrwNpGd563f MdQOHmg5I1BuLoe8zxnT+TJoDqZUPr+lDpS5PyKA5y6fQus42ZGdxa1+FSxcol0aDkiIFurG 0XVY5TqlzPWxdfGyQQQoFmbOu/v8GjldHXO9BdlinEXuhbST2WSZ6caXSqiJkpIr9LS2UHAZ wKokIl/krGXZkaKKk3wXQLiJMwWE7jdOck8c4/rmG6DdqFbUnqKjdiZ69dzjccNY2ismOpS7 xt9M8mAQmYaLscUsQKN75Z6Tx0pvPTaQHl+yf71oDp+3fSY+b73QzSifcijRr/3i9UW0pGLy 8cVYMD2KjdTT6KkkzenF57mA55OGCYA1RskSr2vNRowekYg9LrKDoyTU0GhYLY0eysNIhoSC 6bLsIf3groly5hTMc2WwGIfcgVY3SDtra4NIV/ijzpPpOuNe+LrpIR0MwVQRuAu3Mz/SJ1r6 4i0QVeUqYD/gkuphkqex7ZnfhKAy7gnuD5M93xAWf0S84AQnFMQsrmQVvzZUy9Bqo088qbpu Sg6fIwz2LK3KKvkoEFc/vWobVUTr3s71UCfSSc40NtBb37oDcVUYSeHqx+lfNStXZ+r25BYB ACWC2/gw7Lz4vIohfIOUI9CH3dU4hr1kQ20qLIArUdbglPEwKXULtvUsoQAAAAAAAA== --------------ms080901040002000901000806--