From the document , For communication across nodes the Eager / Rendezvous threshold is defined by the variable I_MPI_EAGER_THRESHOLD (in bytes, default is 256 kB).
I want to tried the performance of different threshold. But when I set the environment variable, I get errors :
 MPI startup(): I_MPI_EAGER_THRESHOLD environment variable is not supported.  MPI startup(): Similar variables: I_MPI_SHM_HEAP_THRESHOLD I_MPI_SHM_CMA_THRESHOLD I_MPI_SHM_EAGER_THRESHOLD I_MPI_LARGE_SCALE_THRESHOLD I_MPI_COLL_SHM_THRESHOLD  MPI startup(): I_MPI_INTRANODE_EAGER_THRESHOLD environment variable is not supported.
The document is last updated on 01/29/2018. I wonder if it is out of date.
From the latest developer reference (version 2021.2), I find no variable which can change the threshold between eager/rendezvous.
So, with oneapi 2021.2, is there any ways that I can control when to use eager protocol and when to use rendezvous protocol?
What's more, according to process-pinning of Intel(R) MPI Library Developer Reference for Linux* OS (2021.2), there are these sentences:
If you do not specify values for any process pinning environment variables, the default settings below are used. For details about these settings, see Environment Variables and Interoperability with OpenMP API. I_MPI_PIN=on I_MPI_PIN_MODE=pm I_MPI_PIN_RESPECT_CPUSET=on I_MPI_PIN_RESPECT_HCA=on I_MPI_PIN_CELL=unit I_MPI_PIN_DOMAIN=auto:compact I_MPI_PIN_ORDER=compact
But when I set this variable, I get 'I_MPI_PIN_MODE variable has been removed from the product, its value is ignored'. The variable is described in the lastest document.
Where could I find the lastest document which is compatible with oneapi 2021.2 I'm using ?
Thanks for reporting to us.
We are investigating your issue and we will get back to you soon with an update.
You can get the details of all available flags using the "impi_info -a" command. And if you want the details of a specific flag, then you can use the command "impi_info -v <flag>".
Thanks & Regards,
You are right, the document https://software.intel.com/content/www/us/en/develop/articles/tuning-the-intel-mpi-library-advanced-... is outdated. Sorry for the inconvenience, we are working on an update.
Since Intel MPI 2019 the I_MPI_EAGER_THRESHOLD is not supported. Intel MPI now relies on the libfabric layer. Please use the environment variables from libfabric described in article https://software.intel.com/content/www/us/en/develop/articles/intel-mpi-library-2019-over-libfabric..... This information will be added to the next Release Notes.
The following information was added to the Intel MPI Release Notes
* Since Intel(R) MPI Library version 2019 environment variable I_MPI_EAGER_THRESHOLD is not supported, please use corresponding libfabric controls instead
And the outdated information about the variable I_MPI_PIN_MODE was removed from