From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f179.google.com ([209.85.223.179]:45466 "EHLO mail-ie0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756696AbaISOxT (ORCPT ); Fri, 19 Sep 2014 10:53:19 -0400 Received: by mail-ie0-f179.google.com with SMTP id rl12so3669832iec.38 for ; Fri, 19 Sep 2014 07:53:18 -0700 (PDT) Message-ID: <541C434F.4060500@gmail.com> Date: Fri, 19 Sep 2014 10:53:03 -0400 From: Austin S Hemmelgarn MIME-Version: 1.0 To: =?UTF-8?B?SG9sZ2VyIEhvZmZzdMOkdHRl?= , linux-btrfs@vger.kernel.org Subject: Re: Performance Issues References: <1411129114.1811.7.camel@zarniwoop.blob> In-Reply-To: Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms010801080905000400050801" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms010801080905000400050801 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable On 2014-09-19 09:51, Holger Hoffst=C3=A4tte wrote: > > On Fri, 19 Sep 2014 13:18:34 +0100, Rob Spanton wrote: > >> I have a particularly uncomplicated setup (a desktop PC with a hard >> disk) and I'm seeing particularly slow performance from btrfs. A `git= >> status` in the linux source tree takes about 46 seconds after dropping= >> caches, whereas on other machines using ext4 this takes about 13s. My= >> mail client (evolution) also seems to perform particularly poorly on >> this setup, and my hunch is that it's spending a lot of time waiting o= n >> the filesystem. > > This is - unfortunately - a particular btrfs oddity/characteristic/flaw= , > whatever you want to call it. git relies a lot on fast stat() calls, > and those seem to be particularly slow with btrfs esp. on rotational > media. I have the same problem with rsync on a freshly mounted volume; > it gets fast (quite so!) after the first run. I find that kind of funny, because regardless of filesystem, stat() is=20 one of the *slowest* syscalls on almost every *nix system in existence. > > The simplest thing to fix this is a "du -s >/dev/null" to pre-cache all= > file inodes. > > I'd also love a technical explanation why this happens and how it could= > be fixed. Maybe it's just a consequence of how the metadata tree(s) > are laid out on disk. While I don't know for certain, I think it's largely just a side effect=20 of the lack of performance tuning in the BTRFS code. > >> I've tried mounting with noatime, and this has had no effect. Anyone >> got any ideas? > > Don't drop the caches :-) > > -h --------------ms010801080905000400050801 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIFuDCC BbQwggOcoAMCAQICAw9gVDANBgkqhkiG9w0BAQ0FADB5MRAwDgYDVQQKEwdSb290IENBMR4w HAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmlu ZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0xNDA4 MDgxMTMwNDRaFw0xNTAyMDQxMTMwNDRaMGMxGDAWBgNVBAMTD0NBY2VydCBXb1QgVXNlcjEj MCEGCSqGSIb3DQEJARYUYWhmZXJyb2luN0BnbWFpbC5jb20xIjAgBgkqhkiG9w0BCQEWE2Fo ZW1tZWxnQG9oaW9ndC5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDdmm8R BM5D6fGiB6rpogPZbLYu6CkU6834rcJepfmxKnLarYUYM593/VGygfaaHAyuc8qLaRA3u1M0 Qp29flqmhv1VDTBZ+zFu6JgHjTDniBii1KOZRo0qV3jC5NvaS8KUM67+eQBjm29LhBWVi3+e a8jLxmogFXV0NGej+GHIr5zA9qKz2WJOEoGh0EfqZ2MQTmozcGI43/oqIYhRj8fRMkWXLUAF WsLzPQMpK19hD8fqwlxQWhBV8gsGRG54K5pyaQsjne7m89SF5M8JkNJPH39tHEvfv2Vhf7EM Y4WGyhLAULSlym1AI1uUHR1FfJaj3AChaEJZli/AdajYsqc7AgMBAAGjggFZMIIBVTAMBgNV HRMBAf8EAjAAMFYGCWCGSAGG+EIBDQRJFkdUbyBnZXQgeW91ciBvd24gY2VydGlmaWNhdGUg Zm9yIEZSRUUgaGVhZCBvdmVyIHRvIGh0dHA6Ly93d3cuQ0FjZXJ0Lm9yZzAOBgNVHQ8BAf8E BAMCA6gwQAYDVR0lBDkwNwYIKwYBBQUHAwQGCCsGAQUFBwMCBgorBgEEAYI3CgMEBgorBgEE AYI3CgMDBglghkgBhvhCBAEwMgYIKwYBBQUHAQEEJjAkMCIGCCsGAQUFBzABhhZodHRwOi8v b2NzcC5jYWNlcnQub3JnMDEGA1UdHwQqMCgwJqAkoCKGIGh0dHA6Ly9jcmwuY2FjZXJ0Lm9y Zy9yZXZva2UuY3JsMDQGA1UdEQQtMCuBFGFoZmVycm9pbjdAZ21haWwuY29tgRNhaGVtbWVs Z0BvaGlvZ3QuY29tMA0GCSqGSIb3DQEBDQUAA4ICAQCr4klxcZU/PDRBpUtlb+d6JXl2dfto OUP/6g19dpx6Ekt2pV1eujpIj5whh5KlCSPUgtHZI7BcksLSczQbxNDvRu6LNKqGJGvcp99k cWL1Z6BsgtvxWKkOmy1vB+2aPfDiQQiMCCLAqXwHiNDZhSkwmGsJ7KHMWgF/dRVDnsl6aOQZ jAcBMpUZxzA/bv4nY2PylVdqJWp9N7x86TF9sda1zRZiyUwy83eFTDNzefYPtc4MLppcaD4g Wt8U6T2ffQfCWVzDirhg4WmDH3MybDItjkSB2/+pgGOS4lgtEBMHzAGQqQ+5PojTHRyqu9Jc O59oIGrTaOtKV9nDeDtzNaQZgygJItJi9GoAl68AmIHxpS1rZUNV6X8ydFrEweFdRTVWhUEL 70Cnx84YBojXv01LYBSZaq18K8cERPLaIrUD2go+2ffjdE9ejvYDhNBllY+ufvRizIjQA1uC OdktVAN6auQob94kOOsWpoMSrzHHvOvVW/kbokmKzaLtcs9+nJoL+vPi2AyzbaoQASVZYOGW pE3daA0F5FJfcPZKCwd5wdnmT3dU1IRUxa5vMmgjP20lkfP8tCPtvZv2mmI2Nw5SaXNY4gVu WQrvkV2in+TnGqgEIwUrLVbx9G6PSYZZs07czhO+Q1iVuKdAwjL/AYK0Us9v50acIzbl5CWw ZGj3wjGCA6EwggOdAgEBMIGAMHkxEDAOBgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6 Ly93d3cuY2FjZXJ0Lm9yZzEiMCAGA1UEAxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEh MB8GCSqGSIb3DQEJARYSc3VwcG9ydEBjYWNlcnQub3JnAgMPYFQwCQYFKw4DAhoFAKCCAfUw GAYJKoZIhvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTQwOTE5MTQ1MzAz WjAjBgkqhkiG9w0BCQQxFgQUszknY/8F9DCKHtVuQzvShpo9pjwwbAYJKoZIhvcNAQkPMV8w XTALBglghkgBZQMEASowCwYJYIZIAWUDBAECMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIA gDANBggqhkiG9w0DAgIBQDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKDCBkQYJKwYBBAGCNxAE MYGDMIGAMHkxEDAOBgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6Ly93d3cuY2FjZXJ0 Lm9yZzEiMCAGA1UEAxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEhMB8GCSqGSIb3DQEJ ARYSc3VwcG9ydEBjYWNlcnQub3JnAgMPYFQwgZMGCyqGSIb3DQEJEAILMYGDoIGAMHkxEDAO BgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6Ly93d3cuY2FjZXJ0Lm9yZzEiMCAGA1UE AxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEhMB8GCSqGSIb3DQEJARYSc3VwcG9ydEBj YWNlcnQub3JnAgMPYFQwDQYJKoZIhvcNAQEBBQAEggEA2hACnnNBhJRba9sSCp0cx6pAOQa9 dBEuYHDtOlv3/ECXoTV4miyeiLtHMPSTBBdnUXWXpj/IcQZvoB5d5Sesy1yXhMwuxuLrRd/e WjVCVllv+kdvcjX9BjhOgvHxy/VCSrQYolK1xLvoZEohlpVdS4gWz7d+Io6qFAaMWD9zk/RK xsOgBg96d7N35lyFvC3CxaiT8z8adwDEz9EMFPL5FvLZErt1ata1zC16jHBy7FBTCZmqaADs 04LmqFK0dW7zahQAqGBoS6PxN2XqcdIKolo/VPtp21wAmZVj91VFFZfELmvvsnX81lw78io5 TOwet76IBpZbwihxf40B5Oe4/AAAAAAAAA== --------------ms010801080905000400050801--