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#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/resource.h>
#if defined(__APPLE__) && defined(__MACH__)
#include <mach/mach.h>
#endif
#include "netcdf.h"
#define filename "file://tmp_cachetest.zarr#mode=zarr,file"
#define chunkSize (size_t)(1<<17) /* 128k */
#define numCells (size_t)(50 * chunkSize)
#define numSteps (size_t)360
static float var[numCells];
size_t getPeakRSS(void)
{
struct rusage rusage;
getrusage( RUSAGE_SELF, &rusage );
#if defined(__APPLE__) && defined(__MACH__)
return (size_t)rusage.ru_maxrss;
#else
return (size_t)(rusage.ru_maxrss * 1024L);
#endif
}
static void
nce(int istat)
{
if (istat != NC_NOERR)
{
fprintf(stderr, "%s\n", nc_strerror(istat));
exit(-1);
}
}
int
main(void)
{
printf("read: chunkSize=%zu, numCells=%zu, numSteps=%zu, filename=%s\n", chunkSize, numCells, numSteps, filename);
int ncId;
nce(nc_open(filename, NC_NOWRITE, &ncId));
int varId;
nce(nc_inq_varid(ncId, "var", &varId));
size_t size, nelems;
float preemption;
nce(nc_get_var_chunk_cache(ncId, varId, &size, &nelems, &preemption));
printf("default chunk cache: size=%zu, nelems=%zu, preemption=%g\n", size, nelems, preemption);
size = 4 * numCells; // one float field at one time step
nelems = 1000;
preemption = 0.5;
nce(nc_set_var_chunk_cache(ncId, varId, size, nelems, preemption));
printf("set chunk cache: size=%zu, nelems=%zu, preemption=%g\n", size, nelems, preemption);
{
for (size_t i = 0; i < numCells; ++i) var[i] = 0.0f;
for (size_t i = 0; i < numSteps; ++i)
{
size_t start[2], count[2];
start[0] = i; start[1] = 0;
count[0] = 1; count[1] = numCells;
nce(nc_get_vara_float(ncId, varId, start, count, var));
}
}
nce(nc_close(ncId));
{
size_t mbused = getPeakRSS() / (1024 * 1024);
printf("Max mem: %zu MB\n", mbused);
if(mbused > 100) {
fprintf(stderr,"*** Failed: used: %luMB expected: < 100MB\n",mbused);
return (1);
}
}
return 0;
}
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