[Lustre-discuss] write RPC & congestion

[Andreas Dilger]

On 2010-09-24, at 18:20, burlen wrote:
> Andreas Dilger wrote:
>> When one of the server threads is ready to process a read/write request it will get or put the data from/to the buffers that the client already prepared.  The number of currently active IO requests is exactly the number of active service threads (up to 512 by default).
> 
> To be sure I understand this, is it correct that each OST has its own pool of service threads? So system wide number of service threads is bound by oss_max_threads*num_osts?

Actuall, the current oss_max_threads tunable is for the whole OSS (as the name implies).  It would be quite useful, in fact, to have a tuneable that like oss_ost_threads (or similar) that is what you suggest.

If you have some time and C coding skills, implementing this would be fairly easily done (see lustre/ost/ost_handler.c and the oss_num_threads tunable handling therein, along with .../lproc_ost.c).

Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.