diff options
Diffstat (limited to 'libbcachefs/sysfs.c')
| -rw-r--r-- | libbcachefs/sysfs.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/libbcachefs/sysfs.c b/libbcachefs/sysfs.c index 251ba822..8c200b55 100644 --- a/libbcachefs/sysfs.c +++ b/libbcachefs/sysfs.c @@ -148,6 +148,7 @@ write_attribute(trigger_btree_key_cache_shrink); write_attribute(trigger_freelist_wakeup); write_attribute(trigger_btree_updates); read_attribute(gc_gens_pos); +__sysfs_attribute(read_fua_test, 0400); read_attribute(uuid); read_attribute(minor); @@ -310,6 +311,116 @@ static void bch2_fs_usage_base_to_text(struct printbuf *out, struct bch_fs *c) prt_printf(out, "nr_inodes:\t%llu\n", b.nr_inodes); } +static int bch2_read_fua_test(struct printbuf *out, struct bch_dev *ca) +{ + struct bch_fs *c = ca->fs; + struct bio *bio = NULL; + void *buf = NULL; + unsigned bs = c->opts.block_size, iters; + u64 end, test_duration = NSEC_PER_SEC * 2; + struct bch2_time_stats stats_nofua, stats_fua, stats_random; + int ret = 0; + + bch2_time_stats_init_no_pcpu(&stats_nofua); + bch2_time_stats_init_no_pcpu(&stats_fua); + bch2_time_stats_init_no_pcpu(&stats_random); + + if (!bch2_dev_get_ioref(c, ca->dev_idx, READ)) { + prt_str(out, "offline\n"); + return 0; + } + + struct block_device *bdev = ca->disk_sb.bdev; + + bio = bio_kmalloc(1, GFP_KERNEL); + if (!bio) { + ret = -ENOMEM; + goto err; + } + + buf = kmalloc(bs, GFP_KERNEL); + if (!buf) + goto err; + + end = ktime_get_ns() + test_duration; + for (iters = 0; iters < 1000 && time_before64(ktime_get_ns(), end); iters++) { + bio_init(bio, bdev, bio->bi_inline_vecs, 1, READ); + bch2_bio_map(bio, buf, bs); + + u64 submit_time = ktime_get_ns(); + ret = submit_bio_wait(bio); + bch2_time_stats_update(&stats_nofua, submit_time); + + if (ret) + goto err; + } + + end = ktime_get_ns() + test_duration; + for (iters = 0; iters < 1000 && time_before64(ktime_get_ns(), end); iters++) { + bio_init(bio, bdev, bio->bi_inline_vecs, 1, REQ_FUA|READ); + bch2_bio_map(bio, buf, bs); + + u64 submit_time = ktime_get_ns(); + ret = submit_bio_wait(bio); + bch2_time_stats_update(&stats_fua, submit_time); + + if (ret) + goto err; + } + + u64 dev_size = ca->mi.nbuckets * bucket_bytes(ca); + + end = ktime_get_ns() + test_duration; + for (iters = 0; iters < 1000 && time_before64(ktime_get_ns(), end); iters++) { + bio_init(bio, bdev, bio->bi_inline_vecs, 1, READ); + bio->bi_iter.bi_sector = (bch2_get_random_u64_below(dev_size) & ~((u64) bs - 1)) >> 9; + bch2_bio_map(bio, buf, bs); + + u64 submit_time = ktime_get_ns(); + ret = submit_bio_wait(bio); + bch2_time_stats_update(&stats_random, submit_time); + + if (ret) + goto err; + } + + u64 ns_nofua = mean_and_variance_get_mean(stats_nofua.duration_stats); + u64 ns_fua = mean_and_variance_get_mean(stats_fua.duration_stats); + u64 ns_rand = mean_and_variance_get_mean(stats_random.duration_stats); + + u64 stddev_nofua = mean_and_variance_get_stddev(stats_nofua.duration_stats); + u64 stddev_fua = mean_and_variance_get_stddev(stats_fua.duration_stats); + u64 stddev_rand = mean_and_variance_get_stddev(stats_random.duration_stats); + + printbuf_tabstop_push(out, 8); + printbuf_tabstop_push(out, 12); + printbuf_tabstop_push(out, 12); + prt_printf(out, "This test must be run on an idle drive for accurate results\n"); + prt_printf(out, "%s\n", dev_name(&ca->disk_sb.bdev->bd_device)); + prt_printf(out, "fua support advertized: %s\n", bdev_fua(bdev) ? "yes" : "no"); + prt_newline(out); + prt_printf(out, "ns:\tlatency\rstddev\r\n"); + prt_printf(out, "nofua\t%llu\r%llu\r\n", ns_nofua, stddev_nofua); + prt_printf(out, "fua\t%llu\r%llu\r\n", ns_fua, stddev_fua); + prt_printf(out, "random\t%llu\r%llu\r\n", ns_rand, stddev_rand); + + bool read_cache = ns_nofua * 2 < ns_rand; + bool fua_cached = read_cache && ns_fua < (ns_nofua + ns_rand) / 2; + + if (!read_cache) + prt_str(out, "reads don't appear to be cached - safe\n"); + else if (!fua_cached) + prt_str(out, "fua reads don't appear to be cached - safe\n"); + else + prt_str(out, "fua reads appear to be cached - unsafe\n"); +err: + kfree(buf); + kfree(bio); + percpu_ref_put(&ca->io_ref); + bch_err_fn(c, ret); + return ret; +} + SHOW(bch2_fs) { struct bch_fs *c = container_of(kobj, struct bch_fs, kobj); @@ -823,6 +934,9 @@ SHOW(bch2_dev) if (attr == &sysfs_open_buckets) bch2_open_buckets_to_text(out, c, ca); + if (attr == &sysfs_read_fua_test) + return bch2_read_fua_test(out, ca); + int opt_id = bch2_opt_lookup(attr->name); if (opt_id >= 0) return sysfs_opt_show(c, ca, opt_id, out); @@ -879,6 +993,8 @@ struct attribute *bch2_dev_files[] = { &sysfs_io_latency_stats_write, &sysfs_congested, + &sysfs_read_fua_test, + /* debug: */ &sysfs_alloc_debug, &sysfs_open_buckets, |