$ perl -v
This is perl 5, version 34, subversion 0 (v5.34.0) built for x86_64-linux
$ echo "sub { [ 200, [], ['OK'] ] }" > app.psgi

##</code><code>##

$ man Gazelle | head
Gazelle(3)          User Contributed Perl Documentation         Gazelle(3)

NAME
       Gazelle - a Preforked Plack Handler for performance freaks

SYNOPSIS
           $ plackup -s Gazelle --port 5003 --max-reqs-per-child 50000 \
                -E production -a app.psgi

$ plackup -s Gazelle --port 5003 --max-reqs-per-child 50000 -E production -a app.psgi &
$ ab -n 10000 -c 100 http://localhost:5003/
(snip)
Document Path:          /
Document Length:        2 bytes

Concurrency Level:      100
Time taken for tests:   0.430 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      940000 bytes
HTML transferred:       20000 bytes
Requests per second:    23277.36 [#/sec] (mean)
Time per request:       4.296 [ms] (mean)
Time per request:       0.043 [ms] (mean, across all concurrent requests)
Transfer rate:          2136.79 [Kbytes/sec] received

##</code><code>##

$ starman --workers 8 --max-requests 1000000 &
$ ab -n 10000 -c 100 http://localhost:5000/
(snip)
Concurrency Level:      100
Time taken for tests:   0.585 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      770000 bytes
HTML transferred:       20000 bytes
Requests per second:    17102.06 [#/sec] (mean)
Time per request:       5.847 [ms] (mean)
Time per request:       0.058 [ms] (mean, across all concurrent requests)
Transfer rate:          1285.99 [Kbytes/sec] received

##</code><code>##

$ plackup -s Feersum --pre-fork=8 --access-log=/dev/null app.psgi &
$ ab -n 10000 -c 100 http://localhost:5000/
(snip)
Concurrency Level:      100
Time taken for tests:   0.542 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      400000 bytes
HTML transferred:       20000 bytes
Requests per second:    18437.56 [#/sec] (mean)
Time per request:       5.424 [ms] (mean)
Time per request:       0.054 [ms] (mean, across all concurrent requests)
Transfer rate:          720.22 [Kbytes/sec] received