Hi all,

My program is creating 4 threads per transaction. Threads doing nothing but simply sleeping.

Now, when transaction ends, I want to wake up all the threads from sleeping. For this I am using pthread_kill() to wake up the threads using signal SIGUSR2.

Problem raises when I put more transactions(eg. 100 trans). My process gets hangup.

What to do ?

4 threads/transaction * 100 transactions ?!? And 400+ pthread_kill(), presumably all at once?

Sounds like a really, really poor design strategy

SUGGESTIONS:
* How can you refactor your design such that you never need more than 10-12 threads at a time (instead of 400++ at a time)?

* How can you insure that the threads you have are actively doing useful work most of the time (instead of idlely consuming resources)?

* Why not consider "signaling" a waiting thread with something like a condition variable or a mutex, instead of a kill?

This is a proxy machine which transfers ip calls from one end to other. Thus it requires these many of threads.

I cant do that because I cant predict no of calls at a single point of time.

I am doing some imp work in kernel space while thread is sleeping in user space. It wont consume any resource while sleeping.

I already tried that, but it requires condition checking, which is also a cpu consuming operation, so want to resolve this issue on signaling basis.

by the way thanx for the reply.

A proxy server certainly does not require "hundreds of threads."

Let me draw a simple real-world analogy of how a fast food restaurant would work with your design:

1. A customer walks into the store.
2. The manager pulls out four boxes and adds a drop of water to the top of each.
3. Pooooff!! "Just Add Water!" Four fully-trained employees appear!
4. Three of the four employees immediately fall asleep. One takes your order.
5. All four employees wake up and wade into the kitchen, which is brimming with employees trying to fill different orders with only one stove and one fryer.
6. After an unpredictable (but very long) amount of time, the employees come out of the kitchen. They hand you the order, then all four of them promptly fall dead.

Now, consider how a grease-joint actually works, and consider how that might influence the design of your server.