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Diffstat (limited to 'libnetdata/adaptive_resortable_list/README.md')
| -rw-r--r-- | libnetdata/adaptive_resortable_list/README.md | 47 |
1 files changed, 23 insertions, 24 deletions
diff --git a/libnetdata/adaptive_resortable_list/README.md b/libnetdata/adaptive_resortable_list/README.md index ab0d7c5a8..0bb99b81c 100644 --- a/libnetdata/adaptive_resortable_list/README.md +++ b/libnetdata/adaptive_resortable_list/README.md @@ -1,10 +1,9 @@ - # Adaptive Re-sortable List (ARL) -This library allows netdata to read a series of `name - value` pairs +This library allows Netdata to read a series of `name - value` pairs in the **fastest possible way**. -ARLs are used all over netdata, as they are the most +ARLs are used all over Netdata, as they are the most CPU utilization efficient way to process `/proc` files. They are used to process both vertical (csv like) and horizontal (one pair per line) `name - value` pairs. @@ -19,9 +18,9 @@ linked list will adapt at the next iteration. During initialization (just once), the caller: -- calls `arl_create()` to create the ARL +- calls `arl_create()` to create the ARL -- calls `arl_expect()` multiple times to register the expected keywords +- calls `arl_expect()` multiple times to register the expected keywords The library will call the `processor()` function (given to `arl_create()`), for each expected keyword found. @@ -34,16 +33,16 @@ Each `name` keyword may have a different `processor()` (by calling For each iteration through the data source, the caller: -- calls `arl_begin()` to initiate a data collection iteration. - This is to be called just ONCE every time the source is re-evaluated. +- calls `arl_begin()` to initiate a data collection iteration. + This is to be called just ONCE every time the source is re-evaluated. -- calls `arl_check()` for each entry read from the file. +- calls `arl_check()` for each entry read from the file. ### Cleanup When the caller exits: -- calls `arl_free()` to destroy this and free all memory. +- calls `arl_free()` to destroy this and free all memory. ### Performance @@ -68,22 +67,22 @@ In the following test we used alternative methods to process, **1M times**, a data source like `/proc/meminfo`, already tokenized, in memory, to extract the same number of expected metrics: -test|code|string comparison|number parsing|duration -:---:|:---:|:---:|:---:|:---:| -1|if-else-if-else-if|`strcmp()`|`strtoull()`|4630.337 ms -2|nested loops|inline `simple_hash()` and `strcmp()`|`strtoull()`|1597.481 ms -3|nested loops|inline `simple_hash()` and `strcmp()`|`str2ull()`|923.523 ms -4|if-else-if-else-if|inline `simple_hash()` and `strcmp()`|`strtoull()`| 854.574 ms -5|if-else-if-else-if|statement expression `simple_hash()` and `strcmp()`|`strtoull()`|912.013 ms -6|if-continue|inline `simple_hash()` and `strcmp()`|`strtoull()`|842.279 ms -7|if-else-if-else-if|inline `simple_hash()` and `strcmp()`|`str2ull()`|602.837 ms -8|ARL|ARL|`strtoull()`|350.360 ms -9|ARL|ARL|`str2ull()`|157.237 ms +|test|code|string comparison|number parsing|duration| +|:--:|:--:|:---------------:|:------------:|:------:| +|1|if-else-if-else-if|`strcmp()`|`strtoull()`|4630.337 ms| +|2|nested loops|inline `simple_hash()` and `strcmp()`|`strtoull()`|1597.481 ms| +|3|nested loops|inline `simple_hash()` and `strcmp()`|`str2ull()`|923.523 ms| +|4|if-else-if-else-if|inline `simple_hash()` and `strcmp()`|`strtoull()`|854.574 ms| +|5|if-else-if-else-if|statement expression `simple_hash()` and `strcmp()`|`strtoull()`|912.013 ms| +|6|if-continue|inline `simple_hash()` and `strcmp()`|`strtoull()`|842.279 ms| +|7|if-else-if-else-if|inline `simple_hash()` and `strcmp()`|`str2ull()`|602.837 ms| +|8|ARL|ARL|`strtoull()`|350.360 ms| +|9|ARL|ARL|`str2ull()`|157.237 ms| Compared to unoptimized code (test No 1: 4.6sec): - - - before ARL netdata was using test No **7** with hashing and a custom `str2ull()` to achieve 602ms. - - the current ARL implementation is test No **9** that needs only 157ms (29 times faster vs unoptimized code, about 4 times faster vs optimized code). + +- before ARL Netdata was using test No **7** with hashing and a custom `str2ull()` to achieve 602ms. +- the current ARL implementation is test No **9** that needs only 157ms (29 times faster vs unoptimized code, about 4 times faster vs optimized code). [Check the source code of this test](../../tests/profile/benchmark-value-pairs.c). @@ -92,4 +91,4 @@ Compared to unoptimized code (test No 1: 4.6sec): Do not use ARL if the a name/keyword may appear more than once in the source data. -[]() +[](<>) |