On Mon, 2020-03-16 at 20:00 -0400, xiubli@xxxxxxxxxx wrote: > From: Xiubo Li <xiubli@xxxxxxxxxx> > > These will be very useful help diagnose problems. > > URL: https://tracker.ceph.com/issues/44533 > Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> > --- > > Changed in V2: > - switch spin lock to cmpxchg > > Changed in V3: > - add the __update_min/max_latency helpers > - minor fix > > fs/ceph/debugfs.c | 26 +++++++++++++++++++++----- > fs/ceph/mds_client.c | 9 +++++++++ > fs/ceph/metric.h | 52 +++++++++++++++++++++++++++++++++++++++++++++++++--- > 3 files changed, 79 insertions(+), 8 deletions(-) > > diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c > index 60f3e307..bcf7215 100644 > --- a/fs/ceph/debugfs.c > +++ b/fs/ceph/debugfs.c > @@ -130,27 +130,43 @@ static int metric_show(struct seq_file *s, void *p) > struct ceph_mds_client *mdsc = fsc->mdsc; > int i, nr_caps = 0; > s64 total, sum, avg = 0; > + unsigned long min, max; > > - seq_printf(s, "item total sum_lat(us) avg_lat(us)\n"); > - seq_printf(s, "-----------------------------------------------------\n"); > + seq_printf(s, "item total sum_lat(us) avg_lat(us) min_lat(us) max_lat(us)\n"); > + seq_printf(s, "-------------------------------------------------------------------------------------\n"); > > total = percpu_counter_sum(&mdsc->metric.total_reads); > sum = percpu_counter_sum(&mdsc->metric.read_latency_sum); > sum = jiffies_to_usecs(sum); > avg = total ? sum / total : 0; > - seq_printf(s, "%-14s%-12lld%-16lld%lld\n", "read", total, sum, avg); > + min = atomic_long_read(&mdsc->metric.read_latency_min); > + min = jiffies_to_usecs(min == ULONG_MAX ? 0 : min); > + max = atomic_long_read(&mdsc->metric.read_latency_max); > + max = jiffies_to_usecs(max); > + seq_printf(s, "%-14s%-12lld%-16lld%-16lld%-16ld%ld\n", "read", > + total, sum, avg, min, max); > > total = percpu_counter_sum(&mdsc->metric.total_writes); > sum = percpu_counter_sum(&mdsc->metric.write_latency_sum); > sum = jiffies_to_usecs(sum); > avg = total ? sum / total : 0; > - seq_printf(s, "%-14s%-12lld%-16lld%lld\n", "write", total, sum, avg); > + min = atomic_long_read(&mdsc->metric.write_latency_min); > + min = jiffies_to_usecs(min == ULONG_MAX ? 0 : min); > + max = atomic_long_read(&mdsc->metric.write_latency_max); > + max = jiffies_to_usecs(max); > + seq_printf(s, "%-14s%-12lld%-16lld%-16lld%-16ld%ld\n", "write", > + total, sum, avg, min, max); > > total = percpu_counter_sum(&mdsc->metric.total_metadatas); > sum = percpu_counter_sum(&mdsc->metric.metadata_latency_sum); > sum = jiffies_to_usecs(sum); > avg = total ? sum / total : 0; > - seq_printf(s, "%-14s%-12lld%-16lld%lld\n", "metadata", total, sum, avg); > + min = atomic_long_read(&mdsc->metric.metadata_latency_min); > + min = jiffies_to_usecs(min == ULONG_MAX ? 0 : min); > + max = atomic_long_read(&mdsc->metric.metadata_latency_max); > + max = jiffies_to_usecs(max); > + seq_printf(s, "%-14s%-12lld%-16lld%-16lld%-16ld%ld\n", "metadata", > + total, sum, avg, min, max); > > seq_printf(s, "\n"); > seq_printf(s, "item total miss hit\n"); > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c > index 5c03ed3..7844aa6 100644 > --- a/fs/ceph/mds_client.c > +++ b/fs/ceph/mds_client.c > @@ -4358,6 +4358,9 @@ static int ceph_mdsc_metric_init(struct ceph_client_metric *metric) > if (ret) > goto err_read_latency_sum; > > + atomic_long_set(&metric->read_latency_min, ULONG_MAX); > + atomic_long_set(&metric->read_latency_max, 0); > + > ret = percpu_counter_init(&metric->total_writes, 0, GFP_KERNEL); > if (ret) > goto err_total_writes; > @@ -4366,6 +4369,9 @@ static int ceph_mdsc_metric_init(struct ceph_client_metric *metric) > if (ret) > goto err_write_latency_sum; > > + atomic_long_set(&metric->write_latency_min, ULONG_MAX); > + atomic_long_set(&metric->write_latency_max, 0); > + > ret = percpu_counter_init(&metric->total_metadatas, 0, GFP_KERNEL); > if (ret) > goto err_total_metadatas; > @@ -4374,6 +4380,9 @@ static int ceph_mdsc_metric_init(struct ceph_client_metric *metric) > if (ret) > goto err_metadata_latency_sum; > > + atomic_long_set(&metric->metadata_latency_min, ULONG_MAX); > + atomic_long_set(&metric->metadata_latency_max, 0); > + > return 0; > > err_metadata_latency_sum: > diff --git a/fs/ceph/metric.h b/fs/ceph/metric.h > index faba142..c9c76d5 100644 > --- a/fs/ceph/metric.h > +++ b/fs/ceph/metric.h > @@ -2,6 +2,10 @@ > #ifndef _FS_CEPH_MDS_METRIC_H > #define _FS_CEPH_MDS_METRIC_H > > +#include <linux/atomic.h> > +#include <linux/percpu.h> > +#include <linux/spinlock.h> > + > /* This is the global metrics */ > struct ceph_client_metric { > atomic64_t total_dentries; > @@ -13,12 +17,18 @@ struct ceph_client_metric { > > struct percpu_counter total_reads; > struct percpu_counter read_latency_sum; > + atomic_long_t read_latency_min; > + atomic_long_t read_latency_max; > > struct percpu_counter total_writes; > struct percpu_counter write_latency_sum; > + atomic_long_t write_latency_min; > + atomic_long_t write_latency_max; > > struct percpu_counter total_metadatas; > struct percpu_counter metadata_latency_sum; > + atomic_long_t metadata_latency_min; > + atomic_long_t metadata_latency_max; > }; > > static inline void ceph_update_cap_hit(struct ceph_client_metric *m) > @@ -31,16 +41,44 @@ static inline void ceph_update_cap_mis(struct ceph_client_metric *m) > percpu_counter_inc(&m->i_caps_mis); > } > > +static inline void __update_min_latency(atomic_long_t *min, unsigned long lat) nit: I don't see a need for the double-underscore prefix here. > +{ > + unsigned long cur, old; > + > + cur = atomic_long_read(min); > + do { > + old = cur; > + if (likely(lat >= old)) > + break; > + } while ((cur = atomic_long_cmpxchg(min, old, lat)) != old); > +} > + > +static inline void __update_max_latency(atomic_long_t *max, unsigned long lat) > +{ > + unsigned long cur, old; > + > + cur = atomic_long_read(max); > + do { > + old = cur; > + if (likely(lat <= old)) > + break; > + } while ((cur = atomic_long_cmpxchg(max, old, lat)) != old); > +} > + > static inline void ceph_update_read_latency(struct ceph_client_metric *m, > unsigned long r_start, > unsigned long r_end, > int rc) > { > + unsigned long lat = r_end - r_start; > + > if (rc < 0 && rc != -ENOENT && rc != -ETIMEDOUT) > return; > > percpu_counter_inc(&m->total_reads); > - percpu_counter_add(&m->read_latency_sum, r_end - r_start); > + percpu_counter_add(&m->read_latency_sum, lat); > + __update_min_latency(&m->read_latency_min, lat); > + __update_max_latency(&m->read_latency_max, lat); > } > > static inline void ceph_update_write_latency(struct ceph_client_metric *m, > @@ -48,11 +86,15 @@ static inline void ceph_update_write_latency(struct ceph_client_metric *m, > unsigned long r_end, > int rc) > { > + unsigned long lat = r_end - r_start; > + > if (rc && rc != -ETIMEDOUT) > return; > > percpu_counter_inc(&m->total_writes); > - percpu_counter_add(&m->write_latency_sum, r_end - r_start); > + percpu_counter_add(&m->write_latency_sum, lat); > + __update_min_latency(&m->write_latency_min, lat); > + __update_max_latency(&m->write_latency_max, lat); > } > > static inline void ceph_update_metadata_latency(struct ceph_client_metric *m, > @@ -60,10 +102,14 @@ static inline void ceph_update_metadata_latency(struct ceph_client_metric *m, > unsigned long r_end, > int rc) > { > + unsigned long lat = r_end - r_start; > + > if (rc && rc != -ENOENT) > return; > > percpu_counter_inc(&m->total_metadatas); > - percpu_counter_add(&m->metadata_latency_sum, r_end - r_start); > + percpu_counter_add(&m->metadata_latency_sum, lat); > + __update_min_latency(&m->metadata_latency_min, lat); > + __update_max_latency(&m->metadata_latency_max, lat); > } > #endif /* _FS_CEPH_MDS_METRIC_H */ Looks good overall though. Note that this makes your stddev patches no longer merge cleanly. They'll need to be rebased on top of this patch. Maybe send it altogether as a series since there are dependencies here? Thanks, -- Jeff Layton <jlayton@xxxxxxxxxx>
