{"action":"created","issue":{"url":"https://api.github.com/repos/root-mirror/root/issues/81","labels_url":"https://api.github.com/repos/root-mirror/root/issues/81/labels{/name}","comments_url":"https://api.github.com/repos/root-mirror/root/issues/81/comments","events_url":"https://api.github.com/repos/root-mirror/root/issues/81/events","html_url":"https://github.com/root-mirror/root/pull/81","id":103344015,"number":81,"title":"Add support for LZ4 as a compression format","user":{"login":"zzxuanyuan","id":5465535,"avatar_url":"https://avatars.githubusercontent.com/u/5465535?v=3","gravatar_id":"","url":"https://api.github.com/users/zzxuanyuan","html_url":"https://github.com/zzxuanyuan","followers_url":"https://api.github.com/users/zzxuanyuan/followers","following_url":"https://api.github.com/users/zzxuanyuan/following{/other_user}","gists_url":"https://api.github.com/users/zzxuanyuan/gists{/gist_id}","starred_url":"https://api.github.com/users/zzxuanyuan/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/zzxuanyuan/subscriptions","organizations_url":"https://api.github.com/users/zzxuanyuan/orgs","repos_url":"https://api.github.com/users/zzxuanyuan/repos","events_url":"https://api.github.com/users/zzxuanyuan/events{/privacy}","received_events_url":"https://api.github.com/users/zzxuanyuan/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":7,"created_at":"2015-08-26T19:10:53Z","updated_at":"2015-09-21T15:14:22Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/root-mirror/root/pulls/81","html_url":"https://github.com/root-mirror/root/pull/81","diff_url":"https://github.com/root-mirror/root/pull/81.diff","patch_url":"https://github.com/root-mirror/root/pull/81.patch"},"body":"This is a updated pull request from #59 The same experiments have been run and performance results are shown here:\r\n\r\n| Algorithm  | compression(write)  | decompression(read)  | Compressed File Size |\r\n|---|---|---|---|\r\n| zlib  | 11.74 MB/s  | 131.06 MB/s  | 181 MB  |\r\n| lzma  | 0.86 MB/s | 17.36 MB/s  | 157 MB  |\r\n| lz4  | 5.22 MB/s  | 143.81 MB/s  | 221 MB  |\r\n\r\nThe following performance is from the root file @pcanal's ticket (https://root.cern.ch/files/CMS_7250E9A5-682D-DF11-8701-002618943934.root). The file is 1.9 GB large, and I tried to decompressed it and it seems its original size is 6.4 GB. The following compression/decompression speeds are calculated by dividing 6.4 GB by the time each test run. @bbockelm , we could discuss implementation details of my tests tomorrow. \r\n\r\n| Algorithm  | compression(write)  | decompression(read)  | Compressed File Size |\r\n|---|---|---|---|\r\n| zlib  | 15.83 MB/s  | 63.23 MB/s  | 1.6 GB  |\r\n| lzma  | 1.28 MB/s | 22.62 MB/s  | 1.2 GB  |\r\n| lz4  | 8.32 MB/s  | 66.53 MB/s  | 1.8 GB  | "},"comment":{"url":"https://api.github.com/repos/root-mirror/root/issues/comments/142011800","html_url":"https://github.com/root-mirror/root/pull/81#issuecomment-142011800","issue_url":"https://api.github.com/repos/root-mirror/root/issues/81","id":142011800,"user":{"login":"pcanal","id":5175087,"avatar_url":"https://avatars.githubusercontent.com/u/5175087?v=3","gravatar_id":"","url":"https://api.github.com/users/pcanal","html_url":"https://github.com/pcanal","followers_url":"https://api.github.com/users/pcanal/followers","following_url":"https://api.github.com/users/pcanal/following{/other_user}","gists_url":"https://api.github.com/users/pcanal/gists{/gist_id}","starred_url":"https://api.github.com/users/pcanal/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/pcanal/subscriptions","organizations_url":"https://api.github.com/users/pcanal/orgs","repos_url":"https://api.github.com/users/pcanal/repos","events_url":"https://api.github.com/users/pcanal/events{/privacy}","received_events_url":"https://api.github.com/users/pcanal/received_events","type":"User","site_admin":false},"created_at":"2015-09-21T15:14:22Z","updated_at":"2015-09-21T15:14:22Z","body":"So the igprof report says that lz4 on the cms file is 20% faster than zlib.   It is odd that it is not reflected in the data as it is supposed to be using \" TTreePerfStats information, which gives us access to the compression-time-only rates.\" ... what am I missing? (i.e. do we have a bug in TTreePerfStas or is the number above not the (de)compression-time-only?\r\n\r\nAlso LZ4HC and zlib-1 are expected to have similar file size.  So we could also add zlib-1 to the table?\r\n\r\nThanks."}}