diff options
Diffstat (limited to 'bin/cat')
| -rw-r--r-- | bin/cat/cat.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/bin/cat/cat.c b/bin/cat/cat.c index 9acd68f..d338742 100644 --- a/bin/cat/cat.c +++ b/bin/cat/cat.c @@ -77,6 +77,17 @@ static void raw_cat(int); static int udom_open(const char *path, int flags); #endif +/* Memory strategy threshold, in pages: if physmem is larger then this, use a + * large buffer */ +#define PHYSPAGES_THRESHOLD (32*1024) + +/* Maximum buffer size in bytes - do not allow it to grow larger than this */ +#define BUFSIZE_MAX (2*1024*1024) + +/* Small (default) buffer size in bytes. It's inefficient for this to be + * smaller than MAXPHYS */ +#define BUFSIZE_SMALL (MAXPHYS) + int main(int argc, char *argv[]) { @@ -247,9 +258,17 @@ raw_cat(int rfd) if (buf == NULL) { if (fstat(wfd, &sbuf)) err(1, "%s", filename); - bsize = MAX(sbuf.st_blksize, 1024); + if (S_ISREG(sbuf.st_mode)) { + /* If there's plenty of RAM, use a large copy buffer */ + if (sysconf(_SC_PHYS_PAGES) > PHYSPAGES_THRESHOLD) + bsize = MIN(BUFSIZE_MAX, MAXPHYS*8); + else + bsize = BUFSIZE_SMALL; + } else + bsize = MAX(sbuf.st_blksize, + (blksize_t)sysconf(_SC_PAGESIZE)); if ((buf = malloc(bsize)) == NULL) - err(1, "buffer"); + err(1, "malloc() failure of IO buffer"); } while ((nr = read(rfd, buf, bsize)) > 0) for (off = 0; nr; nr -= nw, off += nw) |
