bscpkgs/garlic/exp/examples/granularity.nix
2021-03-12 19:33:40 +01:00

189 lines
7.5 KiB
Nix

# This file defines an experiment. It is designed as a function that takes
# several parameters and returns a derivation. This derivation, when built will
# create several scripts that can be executed and launch the experiment.
# These are the inputs to this function: an attribute set which must contain the
# following keys:
{
stdenv
, stdexp
, bsc
, targetMachine
, stages
, garlicTools
}:
# We import in the scope the content of the `stdenv.lib` attribute, which
# contain useful functions like `toString`, which will be used later. This is
# handy to avoid writting `stdenv.lib.tostring`.
with stdenv.lib;
# We also have some functions specific to the garlic benchmark which we import
# as well. Take a look at the garlic/tools.nix file for more details.
with garlicTools;
# The `let` keyword allows us to define some local variables which will be used
# later. It works as the local variable concept in the C language.
let
# Initial variable configuration: every attribute in this set contains lists
# of options which will be used to compute the configuration of the units. The
# cartesian product of all the values will be computed.
varConf = {
# In this case we will vary the columns and rows of the blocksize. This
# configuration will create 3 x 2 = 6 units.
cbs = [ 256 1024 4096 ];
rbs = [ 512 1024 ];
};
# Generate the complete configuration for each unit: genConf is a function
# that accepts the argument `c` and returns a attribute set. The attribute set
# is formed by joining the configuration of the machine (which includes
# details like the number of nodes or the architecture) and the configuration
# that we define for our units.
#
# Notice the use of the `rec` keyword, which allows us to access the elements
# of the set while is being defined.
genConf = c: targetMachine.config // rec {
# These attributes are user defined, and thus the user will need to handle
# them manually. They are not read by the standard pipeline:
# Here we load the `hw` attribute from the machine configuration, so we can
# access it, for example, the number of CPUs per socket as hw.cpusPerSocket.
hw = targetMachine.config.hw;
# These options will be used by the heat app, be we write them here so they
# are stored in the unit configuration.
timesteps = 10;
cols = 1024 * 16; # Columns
rows = 1024 * 16; # Rows
# The blocksize is set to the values passed in the `c` parameter, which will
# be set to one of all the configurations of the cartesian product. for
# example: cbs = 256 and rbs = 512.
# We can also write `inherit (c) cbs rbs`, as is a shorthand notation.
cbs = c.cbs;
rbs = c.rbs;
# The git branch is specified here as well, as will be used when we specify
# the heat app
gitBranch = "garlic/tampi+isend+oss+task";
# -------------------------------------------------------------------------
# These attributes are part of the standard pipeline, and are required for
# each experiment. They are automatically recognized by the standard
# execution pipeline.
# The experiment name:
expName = "example-granularity-heat";
# The experimental unit name. It will be used to create a symlink in the
# index (at /gpfs/projects/bsc15/garlic/$USER/index/) so you can easily find
# the unit. Notice that the symlink is overwritten each time you run a unit
# with the same same.
#
# We use the toString function to convert the numeric value of cbs and rbs
# to a string like: "example-granularity-heat.cbs-256.rbs-512"
unitName = expName +
".cbs-${toString cbs}" +
".rbs-${toString rbs}";
# Repeat the execution of each unit a few times: this option is
# automatically taken by the experiment, which will repeat the execution of
# the program that many times. It is recommended to run the app at least 30
# times, but we only used 10 here for demostration purposes (as it will be
# faster to run)
loops = 10;
# Resources: here we configure the resources in the machine. The queue to be
# used is `debug` as is the fastest for small jobs.
qos = "debug";
# Then the number of MPI processes or tasks per node:
ntasksPerNode = 1;
# And the number of nodes:
nodes = 1;
# We use all the CPUs available in one socket to each MPI process or task.
# Notice that the number of CPUs per socket is not specified directly. but
# loaded from the configuration of the machine that will be used to run our
# experiment. The affinity mask is set accordingly.
cpusPerTask = hw.cpusPerSocket;
# The time will limit the execution of the program in case of a deadlock
time = "02:00:00";
# The job name will appear in the `squeue` and helps to identify what is
# running. Currently is set to the name of the unit.
jobName = unitName;
};
# Using the `varConf` and our function `genConf` we compute a list of the
# complete configuration of every unit.
configs = stdexp.buildConfigs {
inherit varConf genConf;
};
# Now that we have the list of configs, we need to write how that information
# is used to run our program. In our case we will use some params such as the
# number of rows and columns of the input problem or the blocksize as argv
# values.
# The exec stage is used to run a program with some arguments.
exec = {nextStage, conf, ...}: stages.exec {
# All stages require the nextStage attribute, which is passed as parameter.
inherit nextStage;
# Then, we fill the argv array with the elements that will be used when
# running our program. Notice that we load the attributes from the
# configuration which is passed as argument as well.
argv = [
"--rows" conf.rows
"--cols" conf.cols
"--rbs" conf.rbs
"--cbs" conf.cbs
"--timesteps" conf.timesteps
];
# This program requires a file called `head.conf` in the current directory.
# To do it, we run this small script in the `pre` hook, which simple runs
# some commands before running the program. Notice that this command is
# executed in every MPI task.
pre = ''
ln -sf ${nextStage}/etc/heat.conf heat.conf || true
'';
};
# The program stage is only used to specify which program we should run.
# We use this stage to specify build-time parameters such as the gitBranch,
# which will be used to fetch the source code. We use the `override` function
# of the `bsc.garlic.apps.heat` derivation to change the input paramenters.
program = {nextStage, conf, ...}: bsc.garlic.apps.heat.override {
inherit (conf) gitBranch;
};
# Other stages may be defined here, in case that we want to do something
# additional, like running the program under `perf stats` or set some
# envionment variables.
# Once all the stages are defined, we build the pipeline array. The
# `stdexp.stdPipeline` contains the standard pipeline stages, so we don't need
# to specify them. We only specify how we run our program, and what program
# exactly, by adding our `exec` and `program` stages:
pipeline = stdexp.stdPipeline ++ [ exec program ];
# Then, we use the `configs` and the `pipeline` just defined inside the `in`
# part, to build the complete experiment:
in
# The `stdexp.genExperiment` function generates an experiment by calling every
# stage of the pipeline with the different configs, and thus creating
# different units. The result is the top level derivation which is the
# `trebuchet`, which is the script that, when executed, launches the complete
# experiment.
stdexp.genExperiment { inherit configs pipeline; }