> On May 30, 2019, at 6:33 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>
> On Thu, May 30, 2019 at 06:19:54PM -0400, Chuck Lever wrote:
>>
>>
>>> On May 30, 2019, at 5:38 PM, bfields@xxxxxxxxxxxx wrote:
>>>
>>> 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.
>>
>> We now have trace points that can do that too.
>
> You mean, that can report every error (and its value)?
Yes, the nfs_xdr_status trace point reports the error by value and symbolic name.
> I assume having these statistics in mountstats is still useful, though.
>
> --b.
>
>>
>>
>>> --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
>>
>> --
>> Chuck Lever
--
Chuck Lever
