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.Dd May 18, 1998
.Dt HINT 1
.Os
.Sh NAME
.Nm hint
.Nd scalable benchmark for CPU and memory
.Sh SYNOPSIS
.Nm hint
.Sh DESCRIPTION
The program
.Nm
reveals many aspects of computer performance: operation speed,
precision, memory bandwidth, and usable memory size.  HINT measures
"QUIPS" (QUality Improvement Per Second) as a function of time.  "Net
QUIPS" is a single number that summarizes the QUIPS over time.
.Pp
As provided,
.Nm
tests double-precision floating point arithmetic.  The original source
can be re-compiled to test other data types (such as long integers).
The original source should be available directly from
.Pa ftp://ftp.scl.ameslab.gov/pub/HINT/ .
See
.Pa http://www.scl.ameslab.gov/Projects/HINT/
for more information on HINT, including technical reports and an
on-line database of HINT results.
.Pp
The output of
.Nm
is a file in the directory
.Pa data
named
.Pa DOUBLE
which contains five columns:
.Bl -enum
.It
Time
.It
QUIPS
.It
Quality
.It
Subintervals
.It
Memory Used
.El
.Pp
The first two columns are used to produce the QUIPS graph.  The third
and fourth columns are Quality and subintervals.  These columns can be
used to check for loss of quality due to insufficient precision and
poor choices of which rectangle to split. The fifth is useful for
finding the sizes of memory regimes, like where primary cache
saturates or where virtual memory is first invoked.
.Pp
The file is set up in a format suitable for
.Xr gnuplot 1
or similar plotting packages.  QUIPS graphs should be plotted on a
semi-log scale with log of time as the horizontal axis and QUIPS as
the vertical axis. The following gnuplot commands would be suitable to
display the QUIPS graph from the file
.Pa data/DOUBLE :
.nf

set logscale x
plot "data/DOUBLE"

.fi
QUIPS vs. memory use can also be plotted to reveal memory regime sizes,
by using the following
.Xr gnuplot 1
command:
.nf

plot "data/DOUBLE" using 5:2

.fi

.Sh FILES
.Bl -tag -width DOUBLE -compact
.It Pa DOUBLE	output file in the directory
.Pa data
.El
.Sh SEE ALSO
.Xr gnuplot 1
.Sh AUTHOR
.Nm HINT
was developed by the Scalable Computing Laboratory (SCL) of Ames Laboratory,
a US Department of Energy laboratory.
.Sh BUGS
.Nm
only writes its output file in the directory
.Pa data .