On Thu, May 23, 2019 at 04:13:50PM -0400, Dave Wysochanski wrote:
> We often see various error conditions with NFS4.x that show up with
> a very high operation count all completing with tk_status < 0 in a
> short period of time. Add a count to rpc_iostats to record on a
> per-op basis the ops that complete in this manner, which will
> enable lower overhead diagnostics.
Looks like a good idea to me.
It's too bad we can't distinguish the errors. (E.g. ESTALE on a lookup
call is a lot more interesting than ENOENT.) But understood that
maintaining (number of possible errors) * (number of possible ops)
counters is probably overkill, so just counting the number of errors
seems like a good start.
--b.
>
> Signed-off-by: Dave Wysochanski <dwysocha@xxxxxxxxxx>
> ---
> include/linux/sunrpc/metrics.h | 7 ++++++-
> net/sunrpc/stats.c | 8 ++++++--
> 2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/sunrpc/metrics.h b/include/linux/sunrpc/metrics.h
> index 1b3751327575..0ee3f7052846 100644
> --- a/include/linux/sunrpc/metrics.h
> +++ b/include/linux/sunrpc/metrics.h
> @@ -30,7 +30,7 @@
> #include <linux/ktime.h>
> #include <linux/spinlock.h>
>
> -#define RPC_IOSTATS_VERS "1.0"
> +#define RPC_IOSTATS_VERS "1.1"
>
> struct rpc_iostats {
> spinlock_t om_lock;
> @@ -66,6 +66,11 @@ struct rpc_iostats {
> ktime_t om_queue, /* queued for xmit */
> om_rtt, /* RPC RTT */
> om_execute; /* RPC execution */
> + /*
> + * The count of operations that complete with tk_status < 0.
> + * These statuses usually indicate error conditions.
> + */
> + unsigned long om_error_status;
> } ____cacheline_aligned;
>
> struct rpc_task;
> diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
> index 8b2d3c58ffae..737414247ca7 100644
> --- a/net/sunrpc/stats.c
> +++ b/net/sunrpc/stats.c
> @@ -176,6 +176,8 @@ void rpc_count_iostats_metrics(const struct rpc_task *task,
>
> execute = ktime_sub(now, task->tk_start);
> op_metrics->om_execute = ktime_add(op_metrics->om_execute, execute);
> + if (task->tk_status < 0)
> + op_metrics->om_error_status++;
>
> spin_unlock(&op_metrics->om_lock);
>
> @@ -218,13 +220,14 @@ static void _add_rpc_iostats(struct rpc_iostats *a, struct rpc_iostats *b)
> a->om_queue = ktime_add(a->om_queue, b->om_queue);
> a->om_rtt = ktime_add(a->om_rtt, b->om_rtt);
> a->om_execute = ktime_add(a->om_execute, b->om_execute);
> + a->om_error_status += b->om_error_status;
> }
>
> static void _print_rpc_iostats(struct seq_file *seq, struct rpc_iostats *stats,
> int op, const struct rpc_procinfo *procs)
> {
> _print_name(seq, op, procs);
> - seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %llu\n",
> + seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %llu %lu\n",
> stats->om_ops,
> stats->om_ntrans,
> stats->om_timeouts,
> @@ -232,7 +235,8 @@ static void _print_rpc_iostats(struct seq_file *seq, struct rpc_iostats *stats,
> stats->om_bytes_recv,
> ktime_to_ms(stats->om_queue),
> ktime_to_ms(stats->om_rtt),
> - ktime_to_ms(stats->om_execute));
> + ktime_to_ms(stats->om_execute),
> + stats->om_error_status);
> }
>
> void rpc_clnt_show_stats(struct seq_file *seq, struct rpc_clnt *clnt)
> --
> 2.20.1
