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Sun, 06 Jul 2008

Multithreaded POHMELFS crypto processing.

Meanwhile having a rest from various celebrations, I managed to complete receiving multhreaded crypto processing in POHMELFS.
So far it was only tested in debug environment (i.e. zillions of logs and overall miserable performance), but it shows, that different threads pick up the work, both on sending and receiving directions.
There is a limitation though: the same crypto threads are used both for receiving and transmit pathes, so it is possible to saturate them all for example for receiving, so sending will stall. If there are unsufficient crypto threads, waiting for RX crypto processing can take too long, so watchdog transmit scanner will fire up and complete transactions with errors. One can work this around by specifying big enough number of crypto threads or long enough transaction scanning timeout, both are provided via mount option.

I would like to test it in more production-like environment and perform various stresses on it, but I'm far from my working place, so can not do it right now. Which means release will be postponed for tomorrow (if testing will not show regressions or bugs).

This will not be last feature release though: for example POHMELFS does not support extended attributes and ACLs, there is no header checksum (although there is a reserved 32-but field) there may be some features in different areas too, but I do not hurry to implement them, since I need something to put into future POHMELFS changelogs. I think sending the same kernel patch with different words about userspace server changes is not the way to go, so there should be some kernel changes too :)

I will draw up some design notes on how I plan to implement POHMELFS server, and namely how distributed facilities will be done, so far I have quite clear picture in mind, but it needs to be worked out 'on paper' to find rough corners.

Stay tuned!

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