Make import of std.internal.unicode_tables lazy. #5945

wilzbach · 2017-12-19T15:05:58Z

There's no need to open and open and parse the gigantic
std.internal.unicode_tables if it's never needed.

My journey:

std.net.curl -> etc.c.curl -> std.socket -> std.stdio -> std.uni -> std.internal.unicode_tables.

> cd std && echo "import std.uni;" > foo.d
> time dmd -c -o- foo.d
dmd -c -o- foo.d  0.10s user 0.00s system 99% cpu 0.101 total

> time dmd -c -o- foo.d -I..
dmd -c -o- foo.d -I..  0.04s user 0.01s system 99% cpu 0.050 total

Follow-up to #5916

Alternatively a benchmark with avgtime:

> avgtime -r100 dmd -c -o- foo.d
Total time (ms): 9942.26
Repetitions    : 100
Sample mode    : 96 (15 occurrences)
Median time    : 96.908
Avg time       : 99.4226
Std dev.       : 6.38707
Minimum        : 92.079
Maximum        : 120.269
95% conf.int.  : [86.9042, 111.941]  e = 12.5184
99% conf.int.  : [82.9706, 115.875]  e = 16.452
EstimatedAvg95%: [98.1707, 100.674]  e = 1.25184
EstimatedAvg99%: [97.7774, 101.068]  e = 1.6452

> avgtime -r100 dmd -c -o- foo.d -I..
Total time (ms): 4678.42
Repetitions    : 100
Sample mode    : 46 (40 occurrences)
Median time    : 46.537
Avg time       : 46.7842
Std dev.       : 1.39462
Minimum        : 44.338
Maximum        : 53.491
95% conf.int.  : [44.0508, 49.5176]  e = 2.73341
99% conf.int.  : [43.1919, 50.3765]  e = 3.59231
EstimatedAvg95%: [46.5108, 47.0575]  e = 0.273341
EstimatedAvg99%: [46.425, 47.1434]  e = 0.359231

There's no need to open and open and parse the gigantic `std.internal.unicode_tables` if it's never needed.

dlang-bot · 2017-12-19T15:06:00Z

Thanks for your pull request, @wilzbach!

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

wilzbach · 2017-12-19T15:07:13Z

std/uni.d

+alias UpperTriple = AliasSeq!(toUpperIndex, MAX_SIMPLE_UPPER, toUpperTab);
+
+enum MAX_SIMPLE_LOWER = 1043;
+alias LowerTriple = AliasSeq!(toLowerIndex, MAX_SIMPLE_LOWER, toLowerTab);


This is the only bit I couldn't figure out how to do lazily. Better ideas?

Where are these aliases used? Since they were originally private, you may be able to just rewrite the places where they're used to lazily instantiate the definition. Or maybe something like:

private alias UpperTriple() = ...

might do the trick? Not 100% this syntax is supported, or whether it will do what I think it will do.

wilzbach · 2017-12-19T15:10:04Z

Another module:

> cd std && echo "import std.net.curl;" > foo.d
> time dmd -c -o- foo.d
time dmd -c -o- foo.d
dmd -c -o- foo.d  0.24s user 0.04s system 99% cpu 0.288 total

> time dmd -c -o- foo.d -I..
dmd -c -o- foo.d -I..  0.21s user 0.03s system 99% cpu 0.241 total

With avgtime:

> avgtime -r100 dmd -c -o- foo.d
------------------------
Total time (ms): 31928.2
Repetitions    : 100
Sample mode    : 340 (29 occurrences)
Median time    : 315.292
Avg time       : 319.282
Std dev.       : 28.5593
Minimum        : 276.011
Maximum        : 375.411
95% conf.int.  : [263.307, 375.257]  e = 55.9752
99% conf.int.  : [245.718, 392.846]  e = 73.5638
EstimatedAvg95%: [313.685, 324.88]  e = 5.59752
EstimatedAvg99%: [311.926, 326.639]  e = 7.35638

> avgtime -r100 dmd -c -o- foo.d -I..

------------------------
Total time (ms): 24724
Repetitions    : 100
Sample mode    : 230 (46 occurrences)
Median time    : 237.948
Avg time       : 247.24
Std dev.       : 19.8293
Minimum        : 228.172
Maximum        : 301.335
95% conf.int.  : [208.375, 286.105]  e = 38.8647
99% conf.int.  : [196.163, 298.317]  e = 51.0769
EstimatedAvg95%: [243.353, 251.126]  e = 3.88647
EstimatedAvg99%: [242.132, 252.347]  e = 5.10769

wilzbach · 2017-12-23T20:27:42Z

I managed to make a couple of other imports lazy and now std.uni is quite slim:

Before:

parse     foo
importall foo
import    object	(/usr/include/dlang/dmd/object.d)
import    std.uni	(/usr/include/dlang/dmd/std/uni.d)
import    std.meta	(/usr/include/dlang/dmd/std/meta.d)
import    std.traits	(/usr/include/dlang/dmd/std/traits.d)
import    std.functional	(/usr/include/dlang/dmd/std/functional.d)
import    std.range.primitives	(/usr/include/dlang/dmd/std/range/primitives.d)
import    std.internal.unicode_tables	(/usr/include/dlang/dmd/std/internal/unicode_tables.d)
semantic  foo
import    std.range	(/usr/include/dlang/dmd/std/range/package.d)
import    std.typecons	(/usr/include/dlang/dmd/std/typecons.d)
import    core.stdc.stdint	(/usr/include/dlang/dmd/core/stdc/stdint.d)
import    core.stdc.stddef	(/usr/include/dlang/dmd/core/stdc/stddef.d)
import    core.stdc.signal	(/usr/include/dlang/dmd/core/stdc/signal.d)
import    core.stdc.wchar_	(/usr/include/dlang/dmd/core/stdc/wchar_.d)
import    core.stdc.config	(/usr/include/dlang/dmd/core/stdc/config.d)
import    core.stdc.stdarg	(/usr/include/dlang/dmd/core/stdc/stdarg.d)
import    core.stdc.stdlib	(/usr/include/dlang/dmd/core/stdc/stdlib.d)
import    core.stdc.stdio	(/usr/include/dlang/dmd/core/stdc/stdio.d)
import    core.stdc.time	(/usr/include/dlang/dmd/core/stdc/time.d)
import    core.sys.posix.sys.types	(/usr/include/dlang/dmd/core/sys/posix/sys/types.d)
import    core.sys.posix.config	(/usr/include/dlang/dmd/core/sys/posix/config.d)
import    std.array	(/usr/include/dlang/dmd/std/array.d)
import    std.algorithm.iteration	(/usr/include/dlang/dmd/std/algorithm/iteration.d)
import    std.range.interfaces	(/usr/include/dlang/dmd/std/range/interfaces.d)
import    std.format	(/usr/include/dlang/dmd/std/format.d)
import    core.vararg	(/usr/include/dlang/dmd/core/vararg.d)
import    std.exception	(/usr/include/dlang/dmd/std/exception.d)
semantic2 foo
semantic3 foo
code      foo

After

parse     foo
importall foo
import    object	(/home/seb/dlang/druntime/import/object.d)
import    std.uni	(/home/seb/dlang/phobos/std/uni.d)
import    std.meta	(/home/seb/dlang/phobos/std/meta.d)
import    std.traits	(/home/seb/dlang/phobos/std/traits.d)
import    std.functional	(/home/seb/dlang/phobos/std/functional.d)
import    std.range.primitives	(/home/seb/dlang/phobos/std/range/primitives.d)
semantic  foo
semantic2 foo
semantic3 foo
code      foo

quickfur · 2018-01-02T19:46:00Z

std/uni.d

@@ -1588,7 +1588,7 @@ private auto packedArrayView(T)(inout(size_t)* ptr, size_t items) @trusted pure
 // Partially unrolled binary search using Shar's method
 //============================================================================

-string genUnrolledSwitchSearch(size_t size) @safe pure nothrow
+auto genUnrolledSwitchSearch(size_t size) @safe pure nothrow


What's the reason for this change?

quickfur · 2018-01-02T19:52:12Z

std/uni.d

 }

 @safe pure nothrow @nogc @property
 {
-    import std.internal.unicode_tables; // generated file
-
    // It's important to use auto return here, so that the compiler
    // only runs semantic on the return type if the function gets
    // used. Also these are functions rather than templates to not
    // increase the object size of the caller.


I'm not sure I understand the logic of the comment here. Why would templates increase the object size of the caller if they never get used? And does returning auto really suppress the import inside the function body until the function is called?

And does returning auto really suppress the import inside the function body until the function is called?

Yes it does, the compiler needs to have the full function body and run semantic3 on it to determine the return type. Auto return functions behave a lot like templates in that sense, they don't get compiled into the call-site though (AFAIR).

DmitryOlshansky

In general I uge you to check how it performs after this surgery.

Secondly putting all tables to templates means we get to see them duplicated in many object files. As Martin I think he was the last to optimize tgis w.r.t. dynamic libraries

DmitryOlshansky · 2018-01-17T19:00:37Z

std/uni.d

 {
    /// Run-time checked search.
    static auto opCall(C)(in C[] name)
        if (is(C : dchar))
    {
+        // lazily import the big unicode_table
+        mixin(q{


OMG, this going beyond acceptable mutilation imho.

DmitryOlshansky · 2018-01-17T19:00:46Z

std/uni.d

@@ -6095,6 +6099,10 @@ template SetSearcher(alias table, string kind)
    /// Compile-time checked search.
    static @property auto opDispatch(string name)()
    {
+        // lazily import the big unicode_table
+        mixin(q{
+            import std.internal.unicode_tables;


quickfur · 2018-01-17T19:29:25Z

Maybe another approach that will speed up imports without massive mutilation of std.uni might be to generate .di file from unicode_tables.d and import that instead. That way, no actual code change will be required, and we avoid template bloat.

quickfur · 2018-01-25T20:39:23Z

ping @wilzbach @DmitryOlshansky

Any ideas how to move this forward?

CyberShadow · 2018-02-04T11:34:30Z

Can we use .di files here to just provide an interface to the tables, so that the actual tables are parsed only when building Phobos and never when building user code?

wilzbach · 2018-02-04T11:48:48Z

Can we use .di files here to just provide an interface to the tables, so that the actual tables are parsed only when building Phobos and never when building user code?

Yeah that should work in theory, but then we would probably have to change the layout of Phobos a bit (e.g. like Druntime with it's import folder). However, I have an idea and will give it a try.

wilzbach · 2018-02-04T13:51:52Z

Can we use .di files here to just provide an interface to the tables, so that the actual tables are parsed only when building Phobos and never when building user code?

Tried it here: #6123.
tl;dr: DMD's header generation has many bugs, I bumped into two. They can be fixed though (submitted PRs). The big problem though is that the unicode_tables file uses templates too, so they won't be removed by the header file generation.

MartinNowak

Looks OKish though I'm slightly wondering about some function -> template conversions.
Functions have the advantage that they are shipped pre-compiled with the phobos release.

MartinNowak · 2018-02-23T08:40:34Z

std/uni.d


    ushort toUpperIndex(dchar c) { return toUpperIndexTrie[c]; }
    ushort toUpperSimpleIndex(dchar c) { return toUpperSimpleIndexTrie[c]; }
-    dchar toUpperTab(size_t idx) { return toUpperTable[idx]; }
+    dchar toUpperTab()(size_t idx) {


Why not a function?

Actually making things a function above was a decision to also save on codegen time when sth. gets used, because the binary is already in phobos. Imports in function bodies do not leak to the call site, so you also save those when merely calling.
The compiler can still inline things if found appropriate at which point you pay the same price as for instantiating the template.

MartinNowak · 2018-02-23T08:48:30Z

std/uni.d

+        // lazily import the big unicode_table
+        mixin(q{
+            import std.internal.unicode_tables;
+            alias table = } ~ tableName ~ ";");


How about

mixin("std.internal.unicode_tables : table="~tableName~";")

instead?

MartinNowak · 2018-02-23T08:49:51Z

std/uni.d

@@ -6218,7 +6226,7 @@ auto caseEnclose(CodepointSet set)
 /+
    fetch codepoint set corresponding to a name (InBlock or binary property)
 +/
-@trusted CodepointSet getUnicodeSet(in char[] name, bool negated,  bool casefold)


Why make it a template?

MartinNowak · 2018-02-23T08:54:43Z

Yeah that should work in theory, but then we would probably have to change the layout of Phobos a bit (e.g. like Druntime with it's import folder). However, I have an idea and will give it a try.

Dmd prefers importing .di over .d files, so you could have them side by side. But our experience with .di files in druntime was fairly bad, try to avoid them.

LightBender · 2024-10-26T23:47:25Z

PR closed as stalled. If you wish to resurrect it you are welcome to do so.

Make import of std.internal.unicode_tables lazy.

be2aa53

There's no need to open and open and parse the gigantic `std.internal.unicode_tables` if it's never needed.

wilzbach requested a review from DmitryOlshansky as a code owner December 19, 2017 15:05

wilzbach commented Dec 19, 2017

View reviewed changes

wilzbach force-pushed the lazy-uni2 branch from 8fc554e to a9736af Compare December 23, 2017 20:33

wilzbach added 4 commits December 23, 2017 21:48

Make {MIN,MAX}_SIMPLE_LOWER import lazy

39c6d25

Avoid string lambdas as they import the entire world

7466846

Make std.exception imports local

8d58cc8

Templatize std.uni for lazy imports

8336444

wilzbach force-pushed the lazy-uni2 branch from a9736af to 8336444 Compare December 23, 2017 20:48

wilzbach mentioned this pull request Dec 25, 2017

Deprecate public aliases for Regex, StaticRegex, etc #5964

Closed

dlang-bot added Merge:Needs Rebase and removed Merge:Needs Rebase labels Jan 1, 2018

quickfur reviewed Jan 2, 2018

View reviewed changes

dlang-bot added Merge:Needs Rebase and removed Merge:Needs Rebase labels Jan 3, 2018

DmitryOlshansky reviewed Jan 17, 2018

View reviewed changes

wilzbach mentioned this pull request Feb 4, 2018

Add a global convenience package file #5916

Merged

MartinNowak reviewed Feb 23, 2018

View reviewed changes

dlang-bot added Merge:Needs Rebase Review:Needs Work labels May 27, 2021

dlang-bot added the Merge:stalled label May 27, 2021

LightBender closed this Oct 26, 2024

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Make import of std.internal.unicode_tables lazy. #5945

Make import of std.internal.unicode_tables lazy. #5945

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Make import of std.internal.unicode_tables lazy. #5945

Make import of std.internal.unicode_tables lazy. #5945

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