diff options
Diffstat (limited to '')
-rw-r--r-- | libnetdata/procfile/README.md | 71 |
1 files changed, 0 insertions, 71 deletions
diff --git a/libnetdata/procfile/README.md b/libnetdata/procfile/README.md deleted file mode 100644 index 37138bd19..000000000 --- a/libnetdata/procfile/README.md +++ /dev/null @@ -1,71 +0,0 @@ -<!-- -title: "PROCFILE" -custom_edit_url: https://github.com/netdata/netdata/edit/master/libnetdata/procfile/README.md -sidebar_label: "Procfile" -learn_status: "Published" -learn_topic_type: "Tasks" -learn_rel_path: "Developers/libnetdata" ---> - -# PROCFILE - -procfile is a library for reading text data files (i.e `/proc` files) in the fastest possible way. - -## How it works - -The library automatically adapts (through the iterations) its memory so that each file -is read with single `read()` call. - -Then the library splits the file into words, using the supplied separators. -The library also supported quoted words (i.e. strings within of which the separators are ignored). - -### Initialization - -Initially the caller: - -- calls `procfile_open()` to open the file and allocate the structures needed. - -### Iterations - -For each iteration, the caller: - -- calls `procfile_readall()` to read updated contents. - This call also rewinds (`lseek()` to 0) before reading it. - - For every file, a [BUFFER](https://github.com/netdata/netdata/blob/master/libnetdata/buffer/README.md) is used that is automatically adjusted to fit the entire - file contents of the file. So the file is read with a single `read()` call (providing atomicity / consistency when - the data are read from the kernel). - - Once the data are read, 2 arrays of pointers are updated: - - - a `words` array, pointing to each word in the data read - - a `lines` array, pointing to the first word for each line - - This is highly optimized. Both arrays are automatically adjusted to - fit all contents and are updated in a single pass on the data. - - The library provides a number of macros: - - - `procfile_lines()` returns the # of lines read - - `procfile_linewords()` returns the # of words in the given line - - `procfile_word()` returns a pointer the given word # - - `procfile_line()` returns a pointer to the first word of the given line # - - `procfile_lineword()` returns a pointer to the given word # of the given line # - -### Cleanup - -When the caller exits: - -- calls `procfile_free()` to close the file and free all memory used. - -### Performance - -- a **raspberry Pi 1** (the oldest single core one) can process 5.000+ `/proc` files per second. -- a **J1900 Celeron** processor can process 23.000+ `/proc` files per second per core. - -To achieve this kind of performance, the library tries to work in batches so that the code -and the data are inside the processor's caches. - -This library is extensively used in Netdata and its plugins. - - |