On Feb 13, 2012, at 3:05 AM, Benny Halevy wrote:
> Sorry for the late response.
>
> On 2012-02-08 23:04, Adamson, Dros wrote:
>>
>> On Feb 8, 2012, at 12:26 PM, Chuck Lever wrote:
>>
>>> Hi-
>>>
>>> On Feb 8, 2012, at 12:10 PM, Weston Andros Adamson wrote:
>>>
>>>> The per-op stats displayed in /self/proc/mountstats are collected in the sunrpc
>>>
>>> You mean /proc/self/mountstats here.
>>
>> oops!
>>
>>>
>>>> layer and are collected per rpc_client. This has worked for nfs thus far
>>>> since only one nfs_client was ever associated with a mountpoint, but with
>>>> NFS4.1+PNFS+filelayout an nfs mount can have more than one nfs_client.
>>>>
>>>> This can be seen with a pnfs mount where no data server is the same as the MDS -
>>>> all reads, writes and commits will never make it into the current mountstats
>>>> output.
>>>>
>>>> I took the approach of keeping the stats from the MDS and DSs separate in the
>>>> /proc/self/mountstats output to avoid doing too much in the kernel, and to
>>>> expose the fact that these stats are from separate connections (maybe for later
>>>> use).
>>>>
>>>> This method has issues:
>>>>
>>>> 1) even changing the "statvers" of mountstats doesn't stop the userland
>>>> mountstats(8) from trying to parse this output -- and it does so
>>>> incorrectly.
>>>
>>> User land is broken then. :-)
>>
>> Agreed!
>>
>>>
>>>> 2) when using DS multipath this method fails to count operations that happened
>>>> on a different path to the same DS (after a failure).
>>
>> I should have noted that this isn't a problem yet because I haven't submitted the multipath failover patches :)
>>
>>>>
>>>> 3) currently this will display stats twice when DS == MDS.
>>>
>>> Why is this case hard to detect in the kernel or in mountstats?
>>
>> Not hard, just an issue with the current patch.
>>
>>>
>>>>
>>>> So... What should I do here?
>>>>
>>>> A different approach is to add support in net/sunrpc to specify a "parent"
>>>> stat structure so that operations on DS nfs_clients bump stats on
>>>> the main nfs_server->nfs_client->rpc_client. This would take care of all the
>>>> issues with the current patch, but seems like a hack.
>>>
>>> Is this the same as displaying all data in one set of stats?
>>
>> Yes
>>
>>>
>>> Seems like that might be the best next step, then we can split up the MDS and DS stats at some later point.
>
> Splitting up the MDS/DS stats is important to tell when DS I/O is being
> done and how effective it is.
>
> Benny
>
Agreed! It just can't go into mountstats right away (due to statsvers= not being interpreted in mountstats(8)). I'll make a second patch on top of my mountstats changes to add per-DS stats in /proc/fs/nfsfs/ and we can figure out if we want to add it to mountstats later.
Does this sound OK?
-dros
>>
>> Ok, I'll try to do that.
>>
>> Any advice on how to handle the "xprt: …" line? Obviously the different underlying rpc_clients will have different values. I'd have to look at mountstats(8) some more, but I *think* we could just make it a comma separated list.
>>
>> For the 'next step', we can use this patch - we just need to figure out where it should go. Do we keep it in /proc/self/mountstats? I think because of problem #2 we might want to move them out to somewhere in /proc/fs/nfsfs/ along with other per-DS statistics.
>>
>>>
>>>> One task that seems like a good thing to do is to fix mountstats(8) to respect
>>>> the "statsvers" value.
>>>
>>> Agree.
>>
>> I'll do this first.
>>
>> Thanks Chuck!
>>
>> -dros
>>
>>>
>>>>
>>>> Thoughts?
>>>> ---
>>>>
>>>> I cleaned up this patch, but I still have reservations (noted in commit message)
>>>>
>>>> fs/nfs/nfs4filelayout.c | 23 +++++++++++++++++++++++
>>>> fs/nfs/pnfs.h | 20 ++++++++++++++++++++
>>>> fs/nfs/pnfs_dev.c | 25 +++++++++++++++++++++++++
>>>> fs/nfs/super.c | 1 +
>>>> include/linux/nfs_iostat.h | 2 +-
>>>> 5 files changed, 70 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
>>>> index 79be7ac..9410fd0 100644
>>>> --- a/fs/nfs/nfs4filelayout.c
>>>> +++ b/fs/nfs/nfs4filelayout.c
>>>> @@ -33,6 +33,8 @@
>>>> #include <linux/nfs_page.h>
>>>> #include <linux/module.h>
>>>>
>>>> +#include <linux/sunrpc/metrics.h>
>>>> +
>>>> #include "internal.h"
>>>> #include "nfs4filelayout.h"
>>>>
>>>> @@ -918,6 +920,26 @@ filelayout_free_deveiceid_node(struct nfs4_deviceid_node *d)
>>>> nfs4_fl_free_deviceid(container_of(d, struct nfs4_file_layout_dsaddr, id_node));
>>>> }
>>>>
>>>> +static void
>>>> +filelayout_rpc_print_iostats(struct seq_file *m, struct nfs4_deviceid_node *d)
>>>> +{
>>>> + struct nfs4_file_layout_dsaddr *dsaddr;
>>>> + struct nfs4_pnfs_ds *ds;
>>>> + u32 i;
>>>> +
>>>> + dsaddr = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
>>>> +
>>>> + for (i = 0; i < dsaddr->ds_num; i++) {
>>>> + ds = dsaddr->ds_list[i];
>>>> +
>>>> + if (ds && ds->ds_clp) {
>>>> + seq_printf(m, " pnfs dataserver %s\n",
>>>> + ds->ds_remotestr);
>>>> + rpc_print_iostats(m, ds->ds_clp->cl_rpcclient);
>>>> + }
>>>> + }
>>>> +}
>>>> +
>>>> static struct pnfs_layoutdriver_type filelayout_type = {
>>>> .id = LAYOUT_NFSV4_1_FILES,
>>>> .name = "LAYOUT_NFSV4_1_FILES",
>>>> @@ -932,6 +954,7 @@ static struct pnfs_layoutdriver_type filelayout_type = {
>>>> .read_pagelist = filelayout_read_pagelist,
>>>> .write_pagelist = filelayout_write_pagelist,
>>>> .free_deviceid_node = filelayout_free_deveiceid_node,
>>>> + .ds_rpc_print_iostats = filelayout_rpc_print_iostats,
>>>> };
>>>>
>>>> static int __init nfs4filelayout_init(void)
>>>> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
>>>> index 53d593a..0a5e020 100644
>>>> --- a/fs/nfs/pnfs.h
>>>> +++ b/fs/nfs/pnfs.h
>>>> @@ -119,6 +119,9 @@ struct pnfs_layoutdriver_type {
>>>> void (*encode_layoutcommit) (struct pnfs_layout_hdr *layoutid,
>>>> struct xdr_stream *xdr,
>>>> const struct nfs4_layoutcommit_args *args);
>>>> +
>>>> + void (*ds_rpc_print_iostats) (struct seq_file *,
>>>> + struct nfs4_deviceid_node *);
>>>> };
>>>>
>>>> struct pnfs_layout_hdr {
>>>> @@ -239,6 +242,10 @@ void nfs4_init_deviceid_node(struct nfs4_deviceid_node *,
>>>> struct nfs4_deviceid_node *nfs4_insert_deviceid_node(struct nfs4_deviceid_node *);
>>>> bool nfs4_put_deviceid_node(struct nfs4_deviceid_node *);
>>>> void nfs4_deviceid_purge_client(const struct nfs_client *);
>>>> +void nfs4_deviceid_rpc_print_iostats(struct seq_file *seq,
>>>> + const struct nfs_client *clp,
>>>> + const struct pnfs_layoutdriver_type *ld);
>>>> +
>>>>
>>>> static inline int lo_fail_bit(u32 iomode)
>>>> {
>>>> @@ -328,6 +335,14 @@ static inline int pnfs_return_layout(struct inode *ino)
>>>> return 0;
>>>> }
>>>>
>>>> +static inline void
>>>> +pnfs_rpc_print_iostats(struct seq_file *m, struct nfs_server *nfss)
>>>> +{
>>>> + if (!pnfs_enabled_sb(nfss))
>>>> + return;
>>>> + nfs4_deviceid_rpc_print_iostats(m, nfss->nfs_client,
>>>> + nfss->pnfs_curr_ld);
>>>> +}
>>>> #else /* CONFIG_NFS_V4_1 */
>>>>
>>>> static inline void pnfs_destroy_all_layouts(struct nfs_client *clp)
>>>> @@ -429,6 +444,11 @@ static inline int pnfs_layoutcommit_inode(struct inode *inode, bool sync)
>>>> static inline void nfs4_deviceid_purge_client(struct nfs_client *ncl)
>>>> {
>>>> }
>>>> +
>>>> +static inline void
>>>> +pnfs_rpc_print_iostats(struct seq_file *m, struct nfs_server *nfss)
>>>> +{
>>>> +}
>>>> #endif /* CONFIG_NFS_V4_1 */
>>>>
>>>> #endif /* FS_NFS_PNFS_H */
>>>> diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c
>>>> index 4f359d2..277de87 100644
>>>> --- a/fs/nfs/pnfs_dev.c
>>>> +++ b/fs/nfs/pnfs_dev.c
>>>> @@ -115,6 +115,31 @@ nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
>>>> }
>>>> EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
>>>>
>>>> +
>>>> +void
>>>> +nfs4_deviceid_rpc_print_iostats(struct seq_file *seq,
>>>> + const struct nfs_client *clp,
>>>> + const struct pnfs_layoutdriver_type *ld)
>>>> +{
>>>> + struct nfs4_deviceid_node *d;
>>>> + struct hlist_node *n;
>>>> + long h;
>>>> +
>>>> + if (!ld->ds_rpc_print_iostats)
>>>> + return;
>>>> +
>>>> + rcu_read_lock();
>>>> + for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++) {
>>>> + hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[h], node)
>>>> + if (d->ld == ld && d->nfs_client == clp) {
>>>> + if (atomic_read(&d->ref))
>>>> + ld->ds_rpc_print_iostats(seq, d);
>>>> + }
>>>> + }
>>>> + rcu_read_unlock();
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(nfs4_deviceid_rpc_print_iostats);
>>>> +
>>>> /*
>>>> * Remove a deviceid from cache
>>>> *
>>>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>>>> index d18a90b..453e496 100644
>>>> --- a/fs/nfs/super.c
>>>> +++ b/fs/nfs/super.c
>>>> @@ -871,6 +871,7 @@ static int nfs_show_stats(struct seq_file *m, struct dentry *root)
>>>> seq_printf(m, "\n");
>>>>
>>>> rpc_print_iostats(m, nfss->client);
>>>> + pnfs_rpc_print_iostats(m, nfss);
>>>>
>>>> return 0;
>>>> }
>>>> diff --git a/include/linux/nfs_iostat.h b/include/linux/nfs_iostat.h
>>>> index 8866bb3..7fe4605 100644
>>>> --- a/include/linux/nfs_iostat.h
>>>> +++ b/include/linux/nfs_iostat.h
>>>> @@ -21,7 +21,7 @@
>>>> #ifndef _LINUX_NFS_IOSTAT
>>>> #define _LINUX_NFS_IOSTAT
>>>>
>>>> -#define NFS_IOSTAT_VERS "1.0"
>>>> +#define NFS_IOSTAT_VERS "2.0"
>>>>
>>>> /*
>>>> * NFS byte counters
>>>> --
>>>> 1.7.4.4
>>>>
>>>
>>> --
>>> Chuck Lever
>>> chuck[dot]lever[at]oracle[dot]com
>>>
>>>
>>>
>>>
>>
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