NAME

       memtier - redirect malloc calls to memkind memory tiering

SYNOPSIS

       memtier ®.B -r ratio ®.B -t thresholds ®.I program args...

DESCRIPTION

       memtier runs the given program, redirecting memory allocations to different memory tiers based on a given
       policy.   This  allows  unmodified programs to run following a non-greedy allocation scheme that avoids a
       performance cliff when DRAM is exhausted.

OPTIONS

       -r ratio
              Specifies the ratio as a pair of integers separated by a colon, where the first number  gives  the
              relative  share  of  near  DRAM  to  be used while the second number gives "far" memory, be it CXL
              memory or PMEM.  Eg.  "1:4" means that 20% of allocations will use DRAM, 80% PMEM.

              If the ratio is not given, it defaults to the relative share of physically installed memory.

              This version of memtier recognizes only two tiers (DRAM and KMEM_DAX).

       -t thresholds
              Turns on DYNAMIC_THRESHOLD mode where small allocations are served from DRAM and large  ones  from
              far    memory.     The   syntax   is   described   in   depth   in   man   libmemtier,   eg.    -t
              INIT_VAL=1024,MIN_VAL=512,MAX_VAL=65536 starts with a threshold of 1024, then  varies  it  between
              512..65536 attempting to match the requested ratio.

       -v     Displays settings that are passed to libmemtier.

       -h     Shows a help message then exits.

CAVEATS

       This  tool doesn't expose all features of libmemtier.  Only DRAM and KMEM_DAX memory is supported, to use
       FS_DAX you need to configure the library directly, please refer to its man page.

       Or alternatively, you can switch that memory to KMEM_DAX mode.  For that purpose, please  refer  to  "man
       ndctl-reconfigure-namespace" and "man daxctl-reconfigure-device".

SEE ALSO

       libmemtier(7), memkind(3), malloc(3)

Intel Corporation                                  2022-02-21                                         MEMTIER(1)