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| author | Venky Shankar <vshankar@redhat.com> | 2022-03-08 07:42:17 -0500 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2022-03-21 13:35:16 +0100 |
| commit | 367290e6355ce13c17d17f3ec1075beb7ca3224a (patch) | |
| tree | d7070336e2127c775ee163ce696f02da7e1117cc /fs/ceph/metric.c | |
| parent | 8d728c769fd8e5aaaea36288741a4e3493111816 (diff) | |
| download | linux-367290e6355ce13c17d17f3ec1075beb7ca3224a.tar.gz linux-367290e6355ce13c17d17f3ec1075beb7ca3224a.tar.bz2 linux-367290e6355ce13c17d17f3ec1075beb7ca3224a.zip | |
ceph: track average r/w/m latency
Make the math a bit simpler to understand (should not
affect execution speeds).
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph/metric.c')
| -rw-r--r-- | fs/ceph/metric.c | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/fs/ceph/metric.c b/fs/ceph/metric.c index 454d2c93208e..14b6af48b611 100644 --- a/fs/ceph/metric.c +++ b/fs/ceph/metric.c @@ -249,6 +249,7 @@ int ceph_metric_init(struct ceph_client_metric *m) metric->size_max = 0; metric->total = 0; metric->latency_sum = 0; + metric->latency_avg = 0; metric->latency_sq_sum = 0; metric->latency_min = KTIME_MAX; metric->latency_max = 0; @@ -306,20 +307,19 @@ void ceph_metric_destroy(struct ceph_client_metric *m) max = new; \ } -static inline void __update_stdev(ktime_t total, ktime_t lsum, - ktime_t *sq_sump, ktime_t lat) +static inline void __update_mean_and_stdev(ktime_t total, ktime_t *lavg, + ktime_t *sq_sump, ktime_t lat) { - ktime_t avg, sq; - - if (unlikely(total == 1)) - return; - - /* the sq is (lat - old_avg) * (lat - new_avg) */ - avg = DIV64_U64_ROUND_CLOSEST((lsum - lat), (total - 1)); - sq = lat - avg; - avg = DIV64_U64_ROUND_CLOSEST(lsum, total); - sq = sq * (lat - avg); - *sq_sump += sq; + ktime_t avg; + + if (unlikely(total == 1)) { + *lavg = lat; + } else { + /* the sq is (lat - old_avg) * (lat - new_avg) */ + avg = *lavg + div64_s64(lat - *lavg, total); + *sq_sump += (lat - *lavg)*(lat - avg); + *lavg = avg; + } } void ceph_update_metrics(struct ceph_metric *m, @@ -338,6 +338,7 @@ void ceph_update_metrics(struct ceph_metric *m, METRIC_UPDATE_MIN_MAX(m->size_min, m->size_max, size); m->latency_sum += lat; METRIC_UPDATE_MIN_MAX(m->latency_min, m->latency_max, lat); - __update_stdev(total, m->latency_sum, &m->latency_sq_sum, lat); + __update_mean_and_stdev(total, &m->latency_avg, &m->latency_sq_sum, + lat); spin_unlock(&m->lock); } |