From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753867AbbIXLh7 (ORCPT ); Thu, 24 Sep 2015 07:37:59 -0400 Received: from mail-io0-f170.google.com ([209.85.223.170]:36489 "EHLO mail-io0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752560AbbIXLh6 (ORCPT ); Thu, 24 Sep 2015 07:37:58 -0400 Subject: Re: [PATCH 1/3] Make /dev/urandom scalable To: Andi Kleen References: <1442963767-14945-1-git-send-email-andi@firstfloor.org> <5603004A.20801@gmail.com> <20150923232841.GK1747@two.firstfloor.org> Cc: tytso@mit.edu, linux-kernel@vger.kernel.org, kirill.shutemov@linux.intel.com, herbert@gondor.apana.org.au, Andi Kleen From: Austin S Hemmelgarn Message-ID: <5603E083.8020004@gmail.com> Date: Thu, 24 Sep 2015 07:37:39 -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: <20150923232841.GK1747@two.firstfloor.org> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms020509030007090704000200" X-Antivirus: avast! (VPS 150924-0, 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. --------------ms020509030007090704000200 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-09-23 19:28, Andi Kleen wrote: >> I'd almost say that making the partitioning level configurable at >> build time might be useful. I can see possible value to being able >> to at least partition down to physical cores (so, shared between >> HyperThreads on Intel processors, and between Compute Module cores >> on AMD processors), as that could potentially help people running >> large numbers of simulations in parallel. > > I don't like build time size configurations. It doesn't make sense > for simulations to use urandom. It may make sense to have > some run time tunable, but for now that's too much complexity. > So I'll stay with the simpler per node pool for now. Using /dev/urandom directly, yes that doesn't make sense because it=20 consistent returns non-uniformly random numbers when used to generate=20 larger amounts of entropy than the blocking pool can source, but most=20 that use their own PRNG's seed them off of /dev/urandom, and there are=20 cases I've seen of people doing very large numbers (on the order of=20 millions) of short (15 or so minutes run time on decent hardware)=20 simulations that do this. As for a run-time tunable, I agree that that would be better than=20 build-time, and I also agree that it should be done later. The only=20 reason I suggested a build time tunable was that I figured it would be a = lot easier to do than run-time. --------------ms020509030007090704000200 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 hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUwOTI0MTEzNzM5WjBPBgkq hkiG9w0BCQQxQgRAJv8aRas6VYjhXJ7cjey8SW9jZvvnPMtzOc4xUeQzRxZKJpfYp6soSW2L sNQwZ3wgxP3GssUWRDFCW/xIv9pFCDBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxEt+DCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DAN BgkqhkiG9w0BAQEFAASCAgA1ce/iihBj1v0ydXrBJSt+QSWcqKL4Gj5SEh+MqFfFVoG6avcC TLrUgEgSw+/xjy04FLGSu1SVfrRtGuBegcMB2CIPRp1Bu2IPJNMV3gex0n7pMWpZ2QwT5Pyr w4OAgiydlbHVx9hG6VX4VTERYv4gyi1EHLjD6lKwgkT21Xet56HO4Ewf5W1pi7M2hlrBV0yW ec5hSAz0Dr3co7kcm88SBZJ0dYi2Bfam37pyo8kFRnHF+3VMCF+wwUzoFsxUXQn4Zilv/gBf 3OsUhCxn1nJd1vMATix/okcHXlKE5/dIhgbUiVhrwjTzvO//tNUKtd9J9LKmPDA9TKnoxpYu HUTpb6JCg4u3KEhrTDjb5HuSMGF5DpVauP0s1xAsQ08X6oTaHQSdkJje9A6hUQslsiPBre4d 8hPK+0BqzT8cZRw1roxGgOc63LLgQ7PrdJePre+2u2a6LAOKMPgB5M1WbOTqWPGbF/l8bZl7 X+nLYDNFy8Wr+90XysiAwR7Ayo/xPDd7KCuuU50aPT7ZYaowxWp0BLllJEQ3BNgr/PMjDjMm +OTzJKP2mh00kQgyUaSW/03b0L0cBJdT9O1M79XyGEqgSKFYetq8yUDdCG6+xXAxPw2H9k0B gWJFusxA1k3/epEnovz3CghU3XJjWusva6kbf1xs3D1XHaJFTOJPOgd/9AAAAAAAAA== --------------ms020509030007090704000200--