From 2a4be4f6d4029fa001d9070e29d32f00ca5fd00a Mon Sep 17 00:00:00 2001 From: Eric Fischer Date: Mon, 4 Apr 2016 17:00:11 -0700 Subject: [PATCH] Parallel reading is effectively random order, not sequential --- geojson.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/geojson.c b/geojson.c index caea096..3770baa 100644 --- a/geojson.c +++ b/geojson.c @@ -1033,7 +1033,7 @@ void *run_read_parallel(void *v) { perror("map intermediate input"); exit(EXIT_FAILURE); } - madvise(map, a->len, MADV_SEQUENTIAL); + madvise(map, a->len, MADV_RANDOM); // sequential, but from several pointers at once do_read_parallel(map, a->len, a->offset, a->reading, a->reader, a->progress_seq, a->exclude, a->include, a->exclude_all, a->fname, a->basezoom, a->source, a->nlayers, a->droprate, a->initialized, a->initial_x, a->initial_y); @@ -1287,7 +1287,7 @@ void radix1(int *geomfds_in, int *indexfds_in, int inputs, int prefix, int split perror("map index"); exit(EXIT_FAILURE); } - madvise(indexmap, indexst.st_size, MADV_RANDOM); // sequential, but from several pointers at once + madvise(indexmap, indexst.st_size, MADV_RANDOM); // sequential, but from several pointers at once madvise(indexmap, indexst.st_size, MADV_WILLNEED); char *geommap = mmap(NULL, geomst.st_size, PROT_READ, MAP_PRIVATE, geomfds[i], 0); if (geommap == MAP_FAILED) { @@ -1603,7 +1603,7 @@ int read_json(int argc, struct source **sourcelist, char *fname, const char *lay map = mmap(NULL, st.st_size - off, PROT_READ, MAP_PRIVATE, fd, off); // No error if MAP_FAILED because check is below if (map != MAP_FAILED) { - madvise(map, st.st_size - off, MADV_RANDOM); // sequential, but from several pointers at once + madvise(map, st.st_size - off, MADV_RANDOM); // sequential, but from several pointers at once } } }