Bug 43616 - LD_ASSUME_KERNEL changes number of pthreads available.
Summary: LD_ASSUME_KERNEL changes number of pthreads available.
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: glibc   
(Show other bugs)
Version: 7.1
Hardware: i386
OS: Linux
Target Milestone: ---
Assignee: Jakub Jelinek
QA Contact: Aaron Brown
Depends On:
TreeView+ depends on / blocked
Reported: 2001-06-05 21:18 UTC by Ed McKenzie
Modified: 2016-11-24 15:05 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2001-06-05 21:18:05 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Ed McKenzie 2001-06-05 21:18:01 UTC
Description of Problem:
Without LD_ASSUME_KERNEL=2.2.5, the number of pthreads is limited to ~256,
while with that symbol exported the available pthreads rises to ~1024,
which is more consistent with other distributions/platforms.

How Reproducible:

Steps to Reproduce:
1. Write a test program in {python|C|C++} that creates an infinite number
of threads. It should print the number of threads after the first thread
creation fails.
2. Run it without LD_ASSUME_KERNEL=2.2.5.
3. Run it again with that symbol defined.

Actual Results:
Out of the box, RHL 7.1 only supports ~256 threads on i686.

Expected Results:
Other platforms support many more threads. 

Additional Information:

Comment 1 Jakub Jelinek 2001-06-05 21:29:24 UTC
But, unlike when running with LD_ASSUME_KERNEL=2.2.5 (= non-LDT
based threads, no floating thread stacks), this is no hard constant.
It is as easy as
ulimit -s 2048
to get the same thread limit as without LDT based threads, but one
can even
ulimit -s 256
and get loads of threads with smaller stacks.
Of course, threads apps may call setrlimit before doing first
pthread_create instead of relying on ulimit to be called in parent
shell first.

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