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From "Campbell, Lance" <>
Subject Re: [users@httpd] MPM worker - ThreadLimit and ThreadsPerChild
Date Fri, 24 Aug 2018 19:51:49 GMT
I just figured it out.  I found a document that explains just terms.

ThreadsPerChild is the STARTING number of threads per process.
ThreadLimit is the MAX threads that should be created by a child process.

So when calculating ServerLimit you should always use the worst case formula.  
ServerLimt = MaxRequestWorkers divided by ThreadLimit .

ThreadLimit could equal ThreadsPerChild.  Or ThreadLimit could be greater than ThreadsPerChild.


´╗┐On 8/24/18, 2:46 PM, "Eric Covener" <> wrote:

    On Fri, Aug 24, 2018 at 3:42 PM Campbell, Lance <> wrote:
    > Apache 2.4
    > MPM Worker
    > The relationship between ThreadLimit and ThreadsPerChild is not very clear.  These
are some questions I have.
    > Why would you ever want ThreadLimit bigger than ThreadsPerChild?
    Obscure: So you can raise ThreadsPerChild during a graceful restart
    > If you do want it bigger then how do you determine how much bigger it should be?
    Just by how much you'd do the above.
    > If ThreadLimit is bigger than ThreadsPerChild should you then use ThreadLimit instead
of ThreadsPerChild to calculate the ServerLimit?
    Yes, but in practice you just don't need a ThreadLimit higher than
    I would say decide on MaxRequestWorkers first. Then decide on the mix
    between threads and processes you want (ThreadsPerChild) which then
    dictates both ThreadLimit and ServerLimit.
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