Reduce memory use of sty #19549

huonw · 2014-12-05T02:35:14Z

This takes building librustc/lib.rs from using 696 MB to 588 (rustc --no-trans), and 1.99 GB to 1.87 (rustc -O). It also reduces sty down to 32 bytes on platforms with 64-bit pointers, at the expense of some more side-tables in ctxt. I'm sure there's more gains to be had from reducing the size of the side tables (e.g. by making the actual things they're storing smaller).

r? @nikomatsakis

huonw · 2014-12-05T02:40:25Z

My memory measurements are very imprecise (using only GNU time).

Here's the state of sty after this PR:

src/librustc/middle/ty.rs:1145:1: 1182:2 note: total size: 32 bytes
src/librustc/middle/ty.rs:1145 pub enum sty<'tcx> {
src/librustc/middle/ty.rs:1146     ty_bool,
src/librustc/middle/ty.rs:1147     ty_char,
src/librustc/middle/ty.rs:1148     ty_int(ast::IntTy),
src/librustc/middle/ty.rs:1149     ty_uint(ast::UintTy),
src/librustc/middle/ty.rs:1150     ty_float(ast::FloatTy),
                               ...
src/librustc/middle/ty.rs:1146:5: 1146:12 note: variant data: 0 bytes
src/librustc/middle/ty.rs:1146     ty_bool,
                                   ^~~~~~~
src/librustc/middle/ty.rs:1147:5: 1147:12 note: variant data: 0 bytes
src/librustc/middle/ty.rs:1147     ty_char,
                                   ^~~~~~~
src/librustc/middle/ty.rs:1148:5: 1148:23 note: variant data: 1 bytes
src/librustc/middle/ty.rs:1148     ty_int(ast::IntTy),
                                   ^~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1149:5: 1149:25 note: variant data: 1 bytes
src/librustc/middle/ty.rs:1149     ty_uint(ast::UintTy),
                                   ^~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1150:5: 1150:27 note: variant data: 1 bytes
src/librustc/middle/ty.rs:1150     ty_float(ast::FloatTy),
                                   ^~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1158:5: 1158:39 note: variant data: 16 bytes
src/librustc/middle/ty.rs:1158     ty_enum(DefId, &'tcx Substs<'tcx>),
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1159:5: 1159:22 note: variant data: 8 bytes
src/librustc/middle/ty.rs:1159     ty_uniq(Ty<'tcx>),
                                   ^~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1160:5: 1160:11 note: variant data: 0 bytes
src/librustc/middle/ty.rs:1160     ty_str,
                                   ^~~~~~
src/librustc/middle/ty.rs:1161:5: 1161:35 note: variant data: 24 bytes
src/librustc/middle/ty.rs:1161     ty_vec(Ty<'tcx>, Option<uint>), // Second field is length.
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1162:5: 1162:21 note: variant data: 16 bytes
src/librustc/middle/ty.rs:1162     ty_ptr(mt<'tcx>),
                                   ^~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1163:5: 1163:36 note: variant data: 24 bytes
src/librustc/middle/ty.rs:1163     ty_rptr(&'tcx Region, mt<'tcx>),
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1164:5: 1164:37 note: variant data: 8 bytes
src/librustc/middle/ty.rs:1164     ty_bare_fn(&'tcx BareFnTy<'tcx>),
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1165:5: 1165:37 note: variant data: 8 bytes
src/librustc/middle/ty.rs:1165     ty_closure(Box<ClosureTy<'tcx>>),
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1166:5: 1166:33 note: variant data: 8 bytes
src/librustc/middle/ty.rs:1166     ty_trait(Box<TyTrait<'tcx>>),
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1167:5: 1167:41 note: variant data: 16 bytes
src/librustc/middle/ty.rs:1167     ty_struct(DefId, &'tcx Substs<'tcx>),
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1168:5: 1168:64 note: variant data: 24 bytes
src/librustc/middle/ty.rs:1168     ty_unboxed_closure(DefId, &'tcx Region, &'tcx Substs<'tcx>),
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1169:5: 1169:26 note: variant data: 24 bytes
src/librustc/middle/ty.rs:1169     ty_tup(Vec<Ty<'tcx>>),
                                   ^~~~~~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1171:5: 1171:22 note: variant data: 16 bytes
src/librustc/middle/ty.rs:1171     ty_param(ParamTy), // type parameter
                                   ^~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1172:5: 1172:22 note: variant data: 8 bytes
src/librustc/middle/ty.rs:1172     ty_open(Ty<'tcx>), // A deref'ed fat pointer, i.e., a dynamically sized value
                                   ^~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1178:5: 1178:22 note: variant data: 8 bytes
src/librustc/middle/ty.rs:1178     ty_infer(InferTy), // something used only during inference/typeck
                                   ^~~~~~~~~~~~~~~~~
src/librustc/middle/ty.rs:1179:5: 1179:11 note: variant data: 0 bytes
src/librustc/middle/ty.rs:1179     ty_err, // Also only used during inference/typeck, to represent
                                   ^~~~~~

nikomatsakis · 2014-12-05T05:17:31Z

Nice!

arielb1 · 2014-12-08T20:55:34Z

`ty_contents

huonw · 2014-12-08T21:49:24Z

@arielb1, did your comment get truncated?

arielb1 · 2014-12-09T11:35:15Z

@huonw

Sure. But I also mixed up TyContents and TypeFlags so it was irrelevant (only the latter is in TyS, although the former is still a u64 for no reason).

By the way, now that TraitRef is Copy and only 16 bytes long, it may be worth it to stop using Rc<TraitRef> everywhere.

nikomatsakis · 2014-12-10T23:30:31Z

@huonw needs rebase

This current inflates memory use more than 3 times.

This cuts memory use dramatically from the previous commit, and reduces use overall. E.g. the memory usage of `rustc -O librustc/lib.rs` seems to drop 100MB from 1.98GB to 1.88GB (on one run anyway).

This reduces memory use for building librustc with -O from 1.88 to 1.76 GB.

This cuts the ty_bare_fn variant to 48 bytes rather than 56. There doesn't seem to be a noticable memory usage decrease from this.

This allows expanding how many arenas exist without users having to care, since they are all created with CtxtArena::new().

This makes sty only 32 bytes on machines with 64-bit pointers.

(on platforms with 64-bit pointers.) The StmtMac variant is rather large and also fairly rare, so let's optimise the common case.

This replaces required the RUST_LOG=... invocation to make it much more user friendly.

I've totally mangled the history with these rebases; sorry, future programmer!

@nikomatsakis

This takes building `librustc/lib.rs` from using 696 MB to 588 (`rustc --no-trans`), and 1.99 GB to 1.87 (`rustc -O`). It also reduces `sty` down to 32 bytes on platforms with 64-bit pointers, at the expense of some more side-tables in `ctxt`. I'm sure there's more gains to be had from reducing the size of the side tables (e.g. by making the actual things they're storing smaller). r? @nikomatsakis

tomprogrammer · 2014-12-29T18:39:59Z

@huonw Which option did you enable to get the size of the enums/variants told by the compiler?

huonw · 2014-12-31T11:46:02Z

@tomprogrammer, this PR added the -Z print-enum-sizes flag which generates that output.

huonw assigned nikomatsakis Dec 5, 2014

huonw force-pushed the middle-ty-2 branch 3 times, most recently from 70a99e2 to fe3a98f Compare December 5, 2014 22:06

huonw force-pushed the middle-ty-2 branch from fe3a98f to 91200c8 Compare December 12, 2014 04:01

huonw force-pushed the middle-ty-2 branch 4 times, most recently from 09bdbb5 to 53e1b9c Compare December 18, 2014 22:33

huonw force-pushed the middle-ty-2 branch from 53e1b9c to 07fb4c6 Compare December 26, 2014 11:34

huonw force-pushed the middle-ty-2 branch from 07fb4c6 to 8fdd364 Compare December 26, 2014 21:54

huonw force-pushed the middle-ty-2 branch from 8fdd364 to a7c230f Compare December 28, 2014 07:31

Implement debug printing for tcx interner sty's.

7cd6bf6

huonw added 13 commits December 29, 2014 23:55

Store Substs in an arena in the tcx.

4f2b0f0

This current inflates memory use more than 3 times.

Intern substs before storing them in the tcx.

a548f89

This cuts memory use dramatically from the previous commit, and reduces use overall. E.g. the memory usage of `rustc -O librustc/lib.rs` seems to drop 100MB from 1.98GB to 1.88GB (on one run anyway).

Switch Region information from uint to u32.

a33a7d2

This reduces memory use for building librustc with -O from 1.88 to 1.76 GB.

Intern BareFnTys to make sty slightly smaller.

ce3c949

This cuts the ty_bare_fn variant to 48 bytes rather than 56. There doesn't seem to be a noticable memory usage decrease from this.

Collect tcx arenas into a single struct.

add6bb2

This allows expanding how many arenas exist without users having to care, since they are all created with CtxtArena::new().

Intern Region in tcx.

85970d4

This makes sty only 32 bytes on machines with 64-bit pointers.

Print info from the barefn and region interners in the tcx.

06f25b7

Slash the ast::Stmt type from 104 to 24 bytes.

5e5cc67

(on platforms with 64-bit pointers.) The StmtMac variant is rather large and also fairly rare, so let's optimise the common case.

Fix rebase artifacts.

975a57c

Add the -Z print-enum-sizes flag for displaying enum info.

4f7e5ed

This replaces required the RUST_LOG=... invocation to make it much more user friendly.

Rebase fixes.

d442f77

I've totally mangled the history with these rebases; sorry, future programmer!

Update rustc_driver tests.

7c21a0f

More rebase fixes.

91db254

huonw force-pushed the middle-ty-2 branch from a7c230f to 91db254 Compare December 29, 2014 13:11

bors merged commit 91db254 into rust-lang:master Dec 29, 2014

huonw deleted the middle-ty-2 branch December 31, 2014 11:51

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Reduce memory use of sty #19549

Reduce memory use of sty #19549

huonw commented Dec 5, 2014

huonw commented Dec 5, 2014

nikomatsakis commented Dec 5, 2014

arielb1 commented Dec 8, 2014

huonw commented Dec 8, 2014

arielb1 commented Dec 9, 2014

nikomatsakis commented Dec 10, 2014

tomprogrammer commented Dec 29, 2014

huonw commented Dec 31, 2014

Reduce memory use of sty #19549

Reduce memory use of sty #19549

Conversation

huonw commented Dec 5, 2014

huonw commented Dec 5, 2014

nikomatsakis commented Dec 5, 2014

arielb1 commented Dec 8, 2014

huonw commented Dec 8, 2014

arielb1 commented Dec 9, 2014

nikomatsakis commented Dec 10, 2014

tomprogrammer commented Dec 29, 2014

huonw commented Dec 31, 2014