<s>
Unicorn	B-Application
is	O
a	O
Rack	B-Application
HTTP	B-Application
server	I-Application
to	O
serve	O
Ruby	B-Language
web	B-Application
applications	I-Application
on	O
UNIX	O
environment	O
.	O
</s>
<s>
It	O
is	O
optimised	O
to	O
be	O
used	O
with	O
nginx	B-Operating_System
.	O
</s>
<s>
It	O
is	O
based	O
on	O
now	O
deprecated	O
Mongrel	B-Application
1.1.5	O
from	O
2008	O
.	O
</s>
<s>
Unicorn	B-Application
uses	O
a	O
master/worker	O
architecture	O
,	O
where	O
a	O
master	O
process	O
forks	O
worker	O
processes	O
and	O
controls	O
them	O
.	O
</s>
<s>
Unicorn	B-Application
was	O
considered	O
as	O
“	O
one	O
of	O
the	O
most	O
popular	O
servers	O
for	O
Rails	B-Application
”	O
.	O
</s>
<s>
Twitter	B-Application
started	O
to	O
test	O
Unicorn	B-Application
in	O
2010	O
.	O
</s>
<s>
This	O
server	O
is	O
shipped	O
with	O
Discourse	B-Protocol
.	O
</s>
<s>
Their	O
system	O
administrator	O
Sam	O
Saffron	O
noted	O
Unicorn	B-Application
was	O
reliable	O
,	O
as	O
it	O
reaps	O
unresponsive	O
workers	O
.	O
</s>
<s>
Unicorn	B-Application
inspired	O
other	O
projects	O
like	O
Gunicorn	B-Application
,	O
a	O
fork	O
to	O
run	O
Python	O
applications	O
.	O
</s>
<s>
As	O
of	O
2018	O
,	O
projects	O
tend	O
to	O
favour	O
Puma	B-Application
.	O
</s>
<s>
The	O
Heroku	B-General_Concept
hosting	O
provider	O
recommends	O
since	O
2015	O
to	O
migrate	O
from	O
Unicorn	B-Application
to	O
Puma	B-Application
.	O
</s>
<s>
Deliveroo	O
published	O
a	O
benchmark	O
comparing	O
the	O
two	O
servers	O
and	O
concluded	O
“	O
Puma	B-Application
performs	O
better	O
than	O
Unicorn	B-Application
in	O
all	O
tests	O
that	O
were	O
either	O
heavily	O
IO-bound	O
or	O
that	O
interleaved	O
IO	O
and	O
CPU	O
work	O
”	O
,	O
but	O
that	O
Unicorn	B-Application
was	O
still	O
slightly	O
better	O
performing	O
in	O
pure	O
CPU	O
situations	O
.	O
</s>
<s>
GitLab	B-Application
switched	O
to	O
Puma	B-Application
from	O
Unicorn	B-Application
in	O
2020	O
.	O
</s>
