[Bug string/23709] glibc 2.27 lacks sse2 optimized strstr()

[paul.borile at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=23709

--- Comment #12 from paul.borile at gmail dot com ---
I made a test compiling for amd64 the attached program and running it on
different platforms. The test run in 0.5 seconds on a sse2 optimized strstr()
while 8 times slower on a non sse2 optimized strstr(). Example of a fast run :

$ docker run -i ubuntu:16.04 /bin/bash -c "cat > strstr ; chmod +x strstr ;
time ./strstr aa" < ./strstr
Unable to find image 'ubuntu:16.04' locally
16.04: Pulling from library/ubuntu
3b37166ec614: Pull complete 
504facff238f: Pull complete 
ebbcacd28e10: Pull complete 
c7fb3351ecad: Pull complete 
2e3debadcbf7: Pull complete 
Digest: sha256:45ddfa61744947b0b8f7f20b8de70cbcdd441a6a0532f791fd4c09f5e491a8eb
Status: Downloaded newer image for ubuntu:16.04

real    0m0.475s
user    0m0.474s
sys     0m0.000s
matches = 3000000

Example of a slow run :

docker run -i ubuntu:18.04 /bin/bash -c "cat > strstr ; chmod +x strstr ; time
./strstr aa" < ./strstr
Unable to find image 'ubuntu:18.04' locally
18.04: Pulling from library/ubuntu
Digest: sha256:de774a3145f7ca4f0bd144c7d4ffb2931e06634f11529653b23eba85aef8e378
Status: Downloaded newer image for ubuntu:18.04
matches = 3000000

real    0m4.796s
user    0m4.794s
sys     0m0.000s

debian buster is showing the same problem : 

docker run -i debian:buster /bin/bash -c "cat > strstr ; chmod +x strstr ; time
./strstr aa" < ./strstr
Unable to find image 'debian:buster' locally
buster: Pulling from library/debian
1064a561889d: Pull complete 
Digest: sha256:b17f0ca6c2c0c5ad88b3a292e50ad657c87fc165ef1bde4dba57d9616651a9b9
Status: Downloaded newer image for debian:buster
matches = 3000000

real    0m4.871s
user    0m4.871s
sys     0m0.000s

So it is not an ubuntu 18 only problem.

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