Performance- and memory-related work. Three more classes have
been created to avoid regex-based filters internally.
Purpose is to enforce filters which have only one single
wildcard in their pattern, a common occurrence. The filter
pattern is split in two literal string segments.
Similar as above, with the added condition that the filter is
hostname-anchored (`||`). The "Wildcard2" variant is a further
specialization to enforce filters where the only wildcard
is immediately preceded by the `^` special character, again
a very common occurrence.
Using two literal string segments in lieu of regexes allows to
quickly detect a mismatch by just testing the first segment.
Additionally, this reduces memory footprint as regexes are
much more expensive memory-wise than plain strings.
These three new filter classes allow to replace the use of
5276 regex-based filters internally with plain string-based
filters.
Often-called isHnAnchored() has been further fine-tuned to
avoid as much work as possible. I have also observed that
using an arrow function for closure-purpose helps measurably
performance, as per built-in benchmark.
The purpose of using a custom base128 encoder is to
convert array buffers into strings, to allow a direct
string-to-array buffer conversion at load time:
string => array buffer
Whereas a JSON array would require an extra step:
JSON array as string => JS array => array buffer
Turns out that the current use of a custom base128 encoding
results in a significantly larger selfie storage usage when
converting array buffers into strings.
Speculation: possibly the browser convert the strings to
save into JSON strings internally. Since the custom base128
encoder is likely to cause the resulting string to contain
a lot of unprintable ASCII characters, these will need to
be escaped when converted to JSON -- escaped characters
occupy more space than non-escaped ones.
Using a sequence of base 64 numbers means only printable
will be present in the output string, hence no escaping
necessary. I have observed significant reduction in
storage usage for selfie purpose.
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/528#issuecomment-484408622
Following STrie-related work in above issue, I noticed that a large
number of filters in EasyList were filters which only had to match
against the document origin. For instance, among just the top 10
most populous buckets, there were four such buckets with over
hundreds of entries each:
- bits: 72, token: "http", 146 entries
- bits: 72, token: "https", 139 entries
- bits: 88, token: "http", 122 entries
- bits: 88, token: "https", 118 entries
These filters in these buckets have to be matched against all
the network requests.
In order to leverage HNTrie for these filters[1], they are now handled
in a special way so as to ensure they all end up in a single HNTrie
(per bucket), which means that instead of scanning hundreds of entries
per URL, there is now a single scan per bucket per URL for these
apply-everywhere filters.
Now, any filter which fulfill ALL the following condition will be
processed in a special manner internally:
- Is of the form `|https://` or `|http://` or `*`; and
- Does have a `domain=` option; and
- Does not have a negated domain in its `domain=` option; and
- Does not have `csp=` option; and
- Does not have a `redirect=` option
If a filter does not fulfill ALL the conditions above, no change
in behavior.
A filter which matches ALL of the above will be processed in a special
manner:
- The `domain=` option will be decomposed so as to create as many
distinct filter as there is distinct value in the `domain=` option
- This also apply to the `badfilter` version of the filter, which
means it now become possible to `badfilter` only one of the
distinct filter without having to `badfilter` all of them.
- The logger will always report these special filters with only a
single hostname in the `domain=` option.
***
[1] HNTrie is currently WASM-ed on Firefox.
As a development tool for investigation purpose. To use, enter the
following at uBO's dev console:
µBlock.staticNetFilteringEngine.filterClassHistogram()
In the static network filtering engine, `google` token is too
generic and probably leads to too many false positives, beside
causing too large filter bucket.
Implement a plain string trie container class: STrieContainer.
Make use of STrieContainer where beneficial
Some filter buckets can grow quite large, and in such case
coalescing "trieable" filter classes into a single trie reduces
lookup performance and memory usage.
For instance, at time of commit, the filter bucket for the
`ad` keyword contains 919 entries[1].
Coalescing trieable filters of the same class into a single plain
string trie reduced the size of the bucket into 50 entries + two
tries which are scanned only once each whenever the bucket is
visited.
[1] Enter the following code at uBO's dev console:
µBlock.staticNetFilteringEngine.categories.get(0).get(µBlock.urlTokenizer.tokenHashFromString('ad'))
Refactor static network filtering engine code to make use of
ES6's syntactic sugar `class`.
Change first auto-update run from 7 to 5 minutes.
These filters are to be considered obsolete since they can't be
matched against network requests in the webRequest API.
They were probably meant to work when ABP was pre-webext, which
means they are quite probably obsolete and there is no longer
a point for uBO to conveniently translate them into CSP directives.
This removes the derivation of FilterOrigin flavors from
FilterOrigin itself and simplify code paths. FilterOrigin
flavors are small specialized classes, no need to
overcomplicate with derivation.
Specifically, this removes an indirect call to reach the
match() method.
As seen at:
https://whotracks.me/blog/adblockers_performance_study.html
The requests.json.gz file can be downloaded from:
https://cdn.cliqz.com/adblocking/requests_top500.json.gz
Copy the file into ./tmp/requests.json.gz
If the file is present when you build uBO using `make-[target].sh` from
the shell, the resulting package will contain `./assets/requests.json`,
which will be looked-up by the method below to launch a benchmark
session.
From uBO's dev console, launch the benchmark:
µBlock.staticNetFilteringEngine.benchmark();
The usual browser dev tools can be used to obtain useful profiling
data, i.e. start the profiler, call the benchmark method from the
console, then stop the profiler when it completes.
Keep in mind that the measurements at the blog post above where obtained
with ONLY EasyList. The CPU reportedly used was:
https://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i7-6600U+%40+2.60GHz&id=2608
Rename ./tmp/requests.json.gz to something else if you no longer want
./assets/requests.json in the build.
The motivation is to address the higher peak memory usage at launch
time with 3rd-gen HNTrie when a selfie was present.
The selfie generation prior to this change was to collect all
filtering data into a single data structure, and then to serialize
that whole structure at once into storage (using JSON.stringify).
However, HNTrie serialization requires that a large UintArray32 be
converted into a plain JS array, which itslef would be indirectly
converted into a JSON string. This was the main reason why peak
memory usage would be higher at launch from selfie, since the JSON
string would need to be wholly unserialized into JS objects, which
themselves would need to be converted into more specialized data
structures (like that Uint32Array one).
The solution to lower peak memory usage at launch is to refactor
selfie generation to allow a more piecemeal approach: each filtering
component is given the ability to serialize itself rather than to be
forced to be embedded in the master selfie. With this approach, the
HNTrie buffer can now serialize to its own storage by converting the
buffer data directly into a string which can be directly sent to
storage. This avoiding expensive intermediate steps such as
converting into a JS array and then to a JSON string.
As part of the refactoring, there was also opportunistic code
upgrade to ES6 and Promise (eventually all of uBO's code will be
proper ES6).
Additionally, the polyfill to bring getBytesInUse() to Firefox has
been revisited to replace the rather expensive previous
implementation with an implementation with virtually no overhead.
Performance-related work: the logger data has been decoupled
from the DOM -- inspired from CodeMirror's way of efficiently
handling large amout of text data.
This decoupling now makes the logger highly efficient CPU- and
memory-wise, and open the way to more possibilities.
Ability to configure some aspect of the logger behavior and
visuals:
- The hard-coded limit of 5000 entries has been
removed and is now replaced with a variety of
user-configurable settings to enforce the discarding of
logger entries.
- Some columns in the logger output can now be hidden.
The filter list look-up feature has been merged into the
existing overlay dialog used to create URL rules or static
filters, as an entry in a new "Details" pane.
Other issues addressed during refactoring:
- https://github.com/uBlockOrigin/uBlock-issues/issues/280
- https://github.com/gorhill/uBlock/issues/1999
The minimum version supported on Firefox has been bumped
up to 55.0.
commit 7c6cacc59b27660fabacb55d668ef099b222a9e6
Author: Raymond Hill <rhill@raymondhill.net>
Date: Sat Nov 3 08:52:51 2018 -0300
code review: finalize support for wasm-based hntrie
commit 8596ed80e3bdac2c36e3c860b51e7189f6bc8487
Merge: cbe1f2e 000eb82
Author: Raymond Hill <rhill@raymondhill.net>
Date: Sat Nov 3 08:41:40 2018 -0300
Merge branch 'master' of github.com:gorhill/uBlock into trie-wasm
commit cbe1f2e2f38484d42af3204ec7f1b5decd30f99e
Merge: 270fc7f dbb7e80
Author: Raymond Hill <rhill@raymondhill.net>
Date: Fri Nov 2 17:43:20 2018 -0300
Merge branch 'master' of github.com:gorhill/uBlock into trie-wasm
commit 270fc7f9b3b73d79e6355522c1a42ce782fe7e5c
Merge: d2a89cf d693d4f
Author: Raymond Hill <rhill@raymondhill.net>
Date: Fri Nov 2 16:21:08 2018 -0300
Merge branch 'master' of github.com:gorhill/uBlock into trie-wasm
commit d2a89cf28f0816ffd4617c2c7b4ccfcdcc30e1b4
Merge: d7afc78 649f82f
Author: Raymond Hill <rhill@raymondhill.net>
Date: Fri Nov 2 14:54:58 2018 -0300
Merge branch 'master' of github.com:gorhill/uBlock into trie-wasm
commit d7afc78b5f5675d7d34c5a1d0ec3099a77caef49
Author: Raymond Hill <rhill@raymondhill.net>
Date: Fri Nov 2 13:56:11 2018 -0300
finalize wasm-based hntrie implementation
commit e7b9e043cf36ad055791713e34eb0322dec84627
Author: Raymond Hill <rhill@raymondhill.net>
Date: Fri Nov 2 08:14:02 2018 -0300
add first-pass implementation of wasm version of hntrie
commit 1015cb34624f3ef73ace58b58fe4e03dfc59897f
Author: Raymond Hill <rhill@raymondhill.net>
Date: Wed Oct 31 17:16:47 2018 -0300
back up draft work toward experimenting with wasm hntries
A new filtering class has been created: "static extended filtering".
This new class is an umbrella class for more specialized filtering
engines:
- Cosmetic filtering
- Scriptlet filtering
- HTML filtering
HTML filtering is available only on platforms which support modifying
the response body on the fly, so only Firefox 57+ at the moment.
With the ability to modify the response body, HTML filtering has
been introduced: removing elements from the DOM before the source
data has been parsed by the browser.
A consequence of HTML filtering ability is to bring back script tag
filtering feature.
