[Bug 2101201] [NEW] The performance of the rand() function degradation
Public bug reported:
The performance of the rand() function on Ubuntu 22.04 has decreased by 62%
compared to Ubuntu 21.04.
Measured on Ubuntu 21.04: 28.070s
Measured on Ubuntu 22.04: 45.493s
Ubuntu 22.04:
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# hyperfine
./mallocrandfree
Benchmark 1: ./mallocrandfree
Time (mean ± σ): 45.493 s ± 0.229 s[User: 45.489 s, System: 0.001 s]
Range (min … max): 45.246 s … 45.858 s10 runs
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# uname -a
Linux ubuntu 6.5.0-18-generic #18~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Feb 7
11:40:03 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# gcc --version
gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# ldd --version
ldd (Ubuntu GLIBC 2.35-0ubuntu3.6) 2.35
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.
Ubuntu 21.04:
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# hyperfine
./mallocrandfree
Benchmark 1: ./mallocrandfree
Time (mean ± σ): 28.070 s ± 0.162 s[User: 28.069 s, System: 0.001 s]
Range (min … max): 27.772 s … 28.362 s10 runs
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# uname -a
Linux ubuntu 5.11.0-16-generic #17-Ubuntu SMP Wed Apr 14 20:12:43 UTC 2021
x86_64 x86_64 x86_64 GNU/Linux
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# ldd --version
ldd (Ubuntu GLIBC 2.33-0ubuntu5) 2.33
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# gcc --version
gcc (Ubuntu 10.3.0-1ubuntu1) 10.3.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Here is the test code.
#cat mallocrandfree.c
#include
#include
#include
#include
void init()
{
// Tell the user what we are doing.
printf("Running malloc-rand-free test - creating 1,000 byte buffers 2,000,000
times.\n");
fflush(stdout);
// Seed the random number generator with the current time.
srand(time(NULL));
}
void loop()
{
for (int i = 0; i < 200; ++i)
{
//char* bufferPtr = malloc(1000);
char bufferPtr[1000];
for (int j = 0; j < 1000; ++j)
{
bufferPtr[j] = rand() % 256;
//bufferPtr[j] = j;
}
//free(bufferPtr);
}
}
void cleanup()
{
exit(0);
}
int main()
{
init();
loop();
cleanup();
}
Also can measured with time:
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# time
./mallocrandfree
Running malloc-rand-free test - creating 1,000 byte buffers 2,000,000 times.
real0m45.613s
user0m45.602s
sys 0m0.008s
** Affects: ubuntu
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2101201
Title:
The performance of the rand() function degradation
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[Bug 2101201] Re: The performance of the rand() function degradation
** Package changed: ubuntu => glibc (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2101201 Title: The performance of the rand() function degradation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/2101201/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 2101201] Re: The performance of the rand() function degradation
run 20.04 docker on ubuntu 22.04: wrlbuild@0ebf1418845d:/mnt/meta-test/recipes-example/example/files$ time ./mallocrandfree Running malloc-rand-free test - creating 1,000 byte buffers 2,000,000 times. real0m28.753s user0m28.750s sys 0m0.002s wrlbuild@0ebf1418845d:/mnt/meta-test/recipes-example/example/files$ cat /etc/issue Ubuntu 20.04.5 LTS \n \l ubuntu@haixiao:~/meta-test/recipes-example/example/files$ time ./mallocrandfree Running malloc-rand-free test - creating 1,000 byte buffers 2,000,000 times. real0m46.971s user0m46.969s sys 0m0.001s ubuntu@haixiao:~/meta-test/recipes-example/example/files$ cat /etc/issue Ubuntu 22.04.4 LTS \n \l -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2101201 Title: The performance of the rand() function degradation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/2101201/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 2101201] Re: The performance of the rand() function degradation
ubuntu@haixiao:~$ sudo apport-collect 2101201 Package glibc not installed and no hook available, ignoring *** Updating problem report No additional information collected. Press any key to continue... No pending crash reports. Try --help for more information. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2101201 Title: The performance of the rand() function degradation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/2101201/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 2101201] Re: The performance of the rand() function degradation
be0cfd848d9ad7378800d6302bc11467cf2b514f fix this issue. commit be0cfd848d9ad7378800d6302bc11467cf2b514f Author: Wilco Dijkstra Date: Mon Mar 18 15:18:20 2024 + stdlib: Add single-threaded fast path to rand() Improve performance of rand() and __random() by adding a single-threaded fast path. Bench-random-lock shows about 5x speedup on Neoverse V1. Reviewed-by: Adhemerval Zanella Pls refer to https://sourceware.org/bugzilla/show_bug.cgi?id=32777 ** Bug watch added: Sourceware.org Bugzilla #32777 https://sourceware.org/bugzilla/show_bug.cgi?id=32777 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2101201 Title: The performance of the rand() function degradation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/2101201/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 2101201] Re: The performance of the rand() function degradation
apport information
** Tags added: apport-collected jammy
** Description changed:
The performance of the rand() function on Ubuntu 22.04 has decreased by 62%
compared to Ubuntu 21.04.
Measured on Ubuntu 21.04: 28.070s
Measured on Ubuntu 22.04: 45.493s
Ubuntu 22.04:
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# hyperfine
./mallocrandfree
Benchmark 1: ./mallocrandfree
Time (mean ± σ): 45.493 s ± 0.229 s[User: 45.489 s, System: 0.001
s]
Range (min … max): 45.246 s … 45.858 s10 runs
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# uname -a
Linux ubuntu 6.5.0-18-generic #18~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Feb
7 11:40:03 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# gcc
--version
gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# ldd
--version
ldd (Ubuntu GLIBC 2.35-0ubuntu3.6) 2.35
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.
Ubuntu 21.04:
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# hyperfine
./mallocrandfree
Benchmark 1: ./mallocrandfree
Time (mean ± σ): 28.070 s ± 0.162 s[User: 28.069 s, System: 0.001
s]
Range (min … max): 27.772 s … 28.362 s10 runs
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# uname -a
Linux ubuntu 5.11.0-16-generic #17-Ubuntu SMP Wed Apr 14 20:12:43 UTC 2021
x86_64 x86_64 x86_64 GNU/Linux
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# ldd
--version
ldd (Ubuntu GLIBC 2.33-0ubuntu5) 2.33
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# gcc
--version
gcc (Ubuntu 10.3.0-1ubuntu1) 10.3.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Here is the test code.
#cat mallocrandfree.c
#include
#include
#include
#include
void init()
{
// Tell the user what we are doing.
printf("Running malloc-rand-free test - creating 1,000 byte buffers
2,000,000 times.\n");
fflush(stdout);
// Seed the random number generator with the current time.
srand(time(NULL));
}
void loop()
{
for (int i = 0; i < 200; ++i)
{
//char* bufferPtr = malloc(1000);
char bufferPtr[1000];
for (int j = 0; j < 1000; ++j)
{
bufferPtr[j] = rand() % 256;
//bufferPtr[j] = j;
}
//free(bufferPtr);
}
}
void cleanup()
{
exit(0);
}
int main()
{
init();
loop();
cleanup();
}
Also can measured with time:
root@ubuntu:/home/ubuntu/meta-test/recipes-example/example/files# time
./mallocrandfree
Running malloc-rand-free test - creating 1,000 byte buffers 2,000,000 times.
real0m45.613s
user0m45.602s
sys 0m0.008s
+ ---
+ ProblemType: Bug
+ ApportVersion: 2.20.11-0ubuntu82.5
+ Architecture: amd64
+ CasperMD5CheckResult: pass
+ DistroRelease: Ubuntu 22.04
+ InstallationDate: Installed on 2025-03-07 (5 days ago)
+ InstallationMedia: Ubuntu 22.04.4 LTS "Jammy Jellyfish" - Release amd64
(20240220)
+ Package: libc6 2.35-0ubuntu3.9
+ PackageArchitecture: amd64
+ ProcVersionSignature: Ubuntu 6.8.0-52.53~22.04.1-generic 6.8.12
+ RebootRequiredPkgs: Error: path contained symlinks.
+ Tags: jammy
+ Uname: Linux 6.8.0-52-generic x86_64
+ UpgradeStatus: No upgrade log present (probably fresh install)
+ UserGroups: docker sudo
+ _MarkForUpload: True
** Attachment added: "Dependencies.txt"
https://bugs.launchpad.net/bugs/2101201/+attachment/5864337/+files/Dependencies.txt
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https://bugs.launchpad.net/bugs/2101201
Title:
The performance of the rand() function degradation
To manage notifications about this bug go to:
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[Bug 2101201] ProcCpuinfoMinimal.txt
apport information ** Attachment added: "ProcCpuinfoMinimal.txt" https://bugs.launchpad.net/bugs/2101201/+attachment/5864338/+files/ProcCpuinfoMinimal.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2101201 Title: The performance of the rand() function degradation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/2101201/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 2101201] ProcEnviron.txt
apport information ** Attachment added: "ProcEnviron.txt" https://bugs.launchpad.net/bugs/2101201/+attachment/5864339/+files/ProcEnviron.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2101201 Title: The performance of the rand() function degradation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/2101201/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
