cat /proc/sys/kernel/threads-max
The maximum number of threads supported by the lookup system, which is usually very large, is equivalent to the theoretical value
The command has different values on different machines.
On the centos server: 513845
On ubuntu16.04 pc: 62667
Both machines have different CPU and memory configurations
On the centos server: 32768
On ubuntu16.04 pc: 32768
The system limits the maximum number of processes or threads a user can run
-u Number of processes: The maximum number of processes a user can start.
help ulimit
ulimit: ulimit [-SHacdefilmnpqrstuvx] [Restriction] Modify shell resource limits. On systems that allow this type of control, provide what is available to the shell and the processes it creates Control of resources. Options: -S uses `soft'(soft) resource constraints -H uses `hard'(hard) resource constraints -a All current restrictions are reported -b socket cache size Maximum size of core file created by -c -d Maximum size of a process's data area -e highest scheduling priority (`nice') -f has the maximum file size a shell and its subprocesses can write to -i Maximum number of signals that can be suspended -l Maximum memory size a process can lock -m Max Memory Pack Size -n Maximum number of open file descriptors -p Pipe Buffer Size Maximum number of bytes in-q POSIX information queue -r Maximum priority for real-time scheduling -s maximum stack size -t Maximum CPU time in seconds -u Max User Processes -v Virtual Memory Size -x Maximum number of locks If a LIMIT variable is provided, it is a new value for the specified resource; the special LIMIT value is `soft', `hard'and `unlimited', respectively, represent the current soft, hard, and unlimited constraints. Otherwise print the current limit for the specified resource, assuming -f without options Values are 1024 bytes, except -t in seconds and -p in 512 bytes. -u with no range of processes. Exit status: Return is successful unless invalid options are used or errors occur.ulimit -u
Maximum number of processes a user can start.
4096
Used to display current various user process constraints
Linux limits the maximum number of processes per user.To improve performance, depending on device resources
To set the maximum number of processes for each linux user, let me set the maximum number of processes for a linux user to 10,000:
ulimit -u 10000 For Java applications that require many socket connections and keep them open, It is best to modify the number of open files per process by using ulimit-n xx, with a default value of 1024. ulimit -n 4096 Increase the number of files that can be opened per process to 4096, defaulting to 1024 Some of the other important settings recommended to be unlimited are: Data segment length: ulimit-d unlimited Maximum memory size: ulimit-m unlimited Stack size: ulimit-s unlimited CPU time: ulimit-t unlimited Virtual memory: ulimit-v unlimitedTemporarily, for the duration of a shell session logged in through the ulimit command.
Ulimit-a parameter analysis
centos:
core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 256922 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1000000 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 4096 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited
ubuntu:
core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 31333 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 31333 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited
Ali Yun:
[jack@ ~]$ ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 7284 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 65535 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 4096 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited
ulimit -n
Default maximum number of open files
On the centos server: 1000000
On ubuntu16.04 pc: 1024
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