Hi,

I have a RH9 system with 1G of RAM. I start a server process that will initialize by allocating a data structure that's about 500Mb in size. The problem is that as the process initializes itself, the data structure is allocated in swap space rather than in RAM. It's only when the data structure is actually used during computation that it seems to enter RAM from swap. As a consequence, the first time the data structure is instanced, the server takes about 180 seconds to process the request.

From then on it takes less than a second as it should. I also notice that the process size is constant at 437Mb from the start, but the resident size (RSS) in top is 217Mb before the first request, and stays constant at 437Mb after the first request. I do know that there is no demand for RAM when this process is started (i.e. this is the only RAM-hungry process when it starts up). So how do I make it NOT ENTER swap space at all, from the moment it starts? I don't want users to have to wait 180 seconds for their first request.

Thanks much.

pandamatak

PS. Every byte of the entire data structure is accessed for each server request.

3 minute wait , hmm.............you can't just turn the swap on/off any time you want.............try this tho, edit your /etc/fstab and comment out the "swap" line and re-boot, with no swap at all things might run faster when memory is always utilized...............just have to try it and see what happens?!?!?!

Thanks for the suggestion and apologies for the belated response from me.

Yes, commenting out swap in fstab did the trick, but I'd still prefer a cleaner solution if someone has it.

Cheers.

&

Just access whole of the data at startup time, this will move it from the swap to RAM. Then your first request will run fast.
If you want that area to stay on RAM forever, you can use the mlock call to have it staying there.