Nightly rustc provides the print-type-sizes option for printing sizes of all types. It's especially useful for analyzing why futures are soo big, that can hurt performance a lot if such futures are moved.
However, print-type-sizes produces unordered and cluttered output. This crate parses that output, refine it and show top types by a size in compact form.
Features: * Sorts layouts by a type size. * Deduplicates same types. * Merges variants with similar layout. * Shows layouts in compact form. * Limits output.
Firstly, install by using cargo install top-type-sizes or clone the repository and run cargo build --release.
Secondly, compile your project:
sh
$ RUSTFLAGS=-Zprint-type-sizes cargo +nightly build -j 1 > type-sizes.txt
* -Zprint-type-sizes requires the nightly compiler.
* -j 1 is required to avoid incorrect shuffled output.
Finally, use this crate:
sh
$ top-type-sizes < type-sizes.txt | less
sh
$ top-type-sizes --help
``` top-type-sizes 0.1.0
USAGE: top-type-sizes [FLAGS] [OPTIONS]
FLAGS: --help Prints help information -r, --reverse -V, --version Prints version information
OPTIONS:
-h, --hide-less
2032 [async fn body@/home/.cargo/registry/src/github.com-1ecc6299db9ec823/trust-dns-resolver-0.22.0/src/name_server/name_ser
ver_pool.rs:310:1: 374:2] align=8
1 <discriminant>
2031 variant Suspend0
128 opts align=8 offset=0
128 opts
32 err
16 backoff
24 conns
216 request
504 busy
504 par_conns
24 conns
216 request
1 generator_field11
1 generator_field12
1 generator_field13
5 <padding>
216 request_cont align=8
16 __awaitee
1831 variant Suspend1
128 opts align=8 offset=0
128 opts
32 err
16 backoff
24 conns
216 request
504 busy
504 par_conns
24 conns
216 request
1 generator_field11
1 generator_field12
1 generator_field13
5 <padding>
24 requests align=8
8 __awaitee
1792 variant Unresumed, Returned, Panicked
127 <padding>
128 opts align=8
1296 <padding>
24 conns align=8
216 request