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// Extremely hacky server program that will send a standard response
// to every client that connects, then closes the connection. Will
// issue no system calls (as measured by `strace`) after initial setup
// no matter how many requests are served.

// Yes, this program is sorely lacking in error checking. It's a toy
// and not meant to be taken seriously.

// compile with gcc no_syscall_server.c -luring

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# This server demo does a socket hijack in Rack and then saves the socket to a global variable
# to prevent it from being GCed when the Puma thread ends. It will then write "BEEP" to each 
# socket every ten seconds to prevent the connection timing out. During testing, it easily 
# handled up to 65523 connections, after which it ran into the `ulimit` for open file descriptors.
# The bit with the waiting area is there because a normal `Set` is not thread safe and it would
# drop socket due to race conditions. The `Queue` is thread safe and will make sure all sockets
# are preserved.

# run with `rackup -q -p 8000 -o 0.0.0.0 c10k.ru`
# testing: install `ab` and then run `ab -c 20000 -n 20000 <ip adress of server>:8000/

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module Main where

import Utils

import Control.Concurrent
import Control.Concurrent.Chan
import Data.List
import qualified Data.Map.Strict as M
import qualified Data.Set as S
import Data.Range as Range

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{-# LANGUAGE OverloadedStrings, DeriveGeneric, DerivingStrategies, DeriveAnyClass #-}
module Main where

import Prelude hiding (foldl)
import Conduit hiding (connect)
import Data.Attoparsec.ByteString as Attoparsec
import Data.Attoparsec.ByteString.Char8
import qualified Data.ByteString as B
import Data.Aeson
import Data.Conduit.Attoparsec

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-- To benchmark, make sure to expose the GHC.Event.* in /libraries/base/base.cabal,
-- otherwise GHC will complain that they are hidden modules.
import GHC.Event.Manager hiding (closeFd)
import GHC.Event.Internal
import GHC.Event.IoUring as IoUring
import GHC.Event.EPoll as Epoll

import Control.Monad
import Data.Time
import System.Posix.IO

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{-# LANGUAGE OverloadedStrings, BangPatterns, GeneralizedNewtypeDeriving, CPP #-}

module Main where

#include <sys/epoll.h>

import Foreign.C.Error (eNOENT, getErrno, throwErrno,
                        throwErrnoIfMinus1, throwErrnoIfMinus1_)
import Foreign.C.Types
import Foreign.Marshal hiding (void, newArray)

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{-# LANGUAGE OverloadedStrings #-}

module Main where

import Foreign.C.Types
import System.Posix.IO
import System.Posix.Types

import System.Linux.IO.URing
import System.Linux.IO.URing.PollEvent

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(gdb) x/80a 0x42009ffe28-80
0x42009ffdd8:	0x2d68	0x718018 <base_GHCziEventziPSQ_zdwunsafeInsertNew_info+2408>
0x42009ffde8:	0x42003216b1	0x8
0x42009ffdf8:	0x4200613ed9	0x7899c0 <ghczmbignum_GHCziNumziInteger_integerToWordzh_info+48>
0x42009ffe08:	0x769528 <base_GHCziEventziIoUring_zdwconstructUserdata_info+816>	0x0
0x42009ffe18:	0x1	0x825fd0 <stg_ret_p_info>
0x42009ffe28:	0x7ffff45e0940	0x75e7c8 <base_SystemziLinuxziIOziURingziRing_zdwpushSqe_info+264>
0x42009ffe38:	0x7ffff45dc040	0x7ffff45dc100
0x42009ffe48:	0x7ffff45e0940	0xa19
0x42009ffe58:	0x1ff	0xa19

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(gdb) bt
#0  LOOKS_LIKE_CLOSURE_PTR (p=0x318)
    at includes/rts/storage/ClosureMacros.h:255
#1  0x0000000000a044e6 in evacuate (p=0x420193ce48) at rts/sm/Evac.c:591
#2  0x0000000000a14ddb in scavenge_small_bitmap (p=0x420193ce48, size=1, 
    bitmap=0) at rts/sm/Scav.c:289
#3  0x0000000000a17692 in scavenge_stack (p=0x420193ce48, 
    stack_end=0x420193cf80) at rts/sm/Scav.c:1923
#4  0x0000000000a16e15 in scavenge_one (p=0x420193cbf8) at rts/sm/Scav.c:1484
#5  0x0000000000a17218 in scavenge_mutable_list (bd=0x4201500880, gen=0xcb88e0)

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{-# LANGUAGE OverloadedStrings #-}
-- Echo server program
module Main (main) where

import Control.Concurrent
import Control.Concurrent.MVar
import qualified Control.Exception as E
import Control.Monad (unless, forever, void)
import qualified Data.ByteString as S
import qualified Data.ByteString.Char8 as S8