diff --git a/usr.bin/top/machine.c b/usr.bin/top/machine.c index b4cd29dab87..a76d77a80ce 100644 --- a/usr.bin/top/machine.c +++ b/usr.bin/top/machine.c @@ -293,17 +293,27 @@ machine_init(struct statics *statics) size = sizeof(carc_en); if (arc_enabled && sysctlbyname("vfs.zfs.compressed_arc_enabled", &carc_en, &size, - NULL, 0) == 0 && carc_en == 1) - carc_enabled = 1; + NULL, 0) == 0 && carc_en == 1) { + uint64_t uncomp_sz; + + /* + * Don't report compression stats if no data is in the ARC. + * Otherwise, we end up printing a blank line. + */ + size = sizeof(uncomp_sz); + if (sysctlbyname("kstat.zfs.misc.arcstats.uncompressed_size", + &uncomp_sz, &size, NULL, 0) == 0 && uncomp_sz != 0) + carc_enabled = 1; + } kd = kvm_open(NULL, _PATH_DEVNULL, NULL, O_RDONLY, "kvm_open"); if (kd == NULL) return (-1); size = sizeof(nswapdev); - if (sysctlbyname("vm.nswapdev", &nswapdev, &size, NULL, - 0) == 0 && nswapdev != 0) - has_swap = 1; + if (sysctlbyname("vm.nswapdev", &nswapdev, &size, NULL, 0) == 0 && + nswapdev != 0) + has_swap = 1; GETSYSCTL("kern.ccpu", ccpu);