linux/net/sunrpc
Chuck Lever ff8399709e SUNRPC: Replace jiffies-based metrics with ktime-based metrics
Currently RPC performance metrics that tabulate elapsed time use
jiffies time values.  This is problematic on systems that use slow
jiffies (for instance 100HZ systems built for paravirtualized
environments).  It is also a problem for computing precise latency
statistics for advanced network transports, such as InfiniBand,
that can have round-trip latencies significanly faster than a single
clock tick.

For the RPC client, adopt the high resolution time stamp mechanism
already used by the network layer and blktrace: ktime.

We use ktime format time stamps for all internal computations, and
convert to milliseconds for presentation.  As a result, we need only
addition operations in the performance critical paths; multiply/divide
is required only for presentation.

We could report RTT metrics in microseconds.  In fact the mountstats
format is versioned to accomodate exactly this kind of interface
improvement.

For now, however, we'll stay with millisecond precision for
presentation to maintain backwards compatibility with the handful of
currently deployed user space tools.  At a later point, we'll move to
an API such as BDI_STATS where a finer timestamp precision can be
reported.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-05-14 15:09:33 -04:00
..
auth_gss gss_krb5: Advertise rc4-hmac enctype support in the rpcsec_gss/krb5 upcall 2010-05-14 15:09:21 -04:00
xprtrdma SUNRPC: Fail over more quickly on connect errors 2010-05-14 15:09:30 -04:00
addr.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
auth_generic.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
auth_null.c headers: utsname.h redux 2009-09-23 18:13:10 -07:00
auth_unix.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
auth.c SUNRPC: Fix a bug in rpcauth_prune_expired 2010-04-22 15:35:55 -04:00
backchannel_rqst.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
bc_svc.c SUNRPC: Fix a use after free bug with the NFSv4.1 backchannel 2010-03-22 05:32:44 -04:00
cache.c net: Move && and || to end of previous line 2009-11-29 16:55:45 -08:00
clnt.c SUNRPC: Cleanup - make rpc_new_task() call rpc_release_calldata on failure 2010-05-14 15:09:29 -04:00
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-04-03 15:24:35 -07:00
Makefile SUNRPC: Provide functions for managing universal addresses 2009-08-09 15:09:34 -04:00
rpc_pipe.c sunrpc: handle allocation errors from __rpc_lookup_create() 2010-03-22 05:34:13 -04:00
rpcb_clnt.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sched.c SUNRPC: Replace jiffies-based metrics with ktime-based metrics 2010-05-14 15:09:33 -04:00
socklib.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
stats.c SUNRPC: Replace jiffies-based metrics with ktime-based metrics 2010-05-14 15:09:33 -04:00
sunrpc_syms.c SUNRPC: Use a cached RPC client and transport for rpcbind upcalls 2009-12-03 15:58:56 -05:00
sunrpc.h nfsd41: sunrpc: Added rpc server-side backchannel handling 2009-09-11 15:04:16 -04:00
svc_xprt.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
svc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
svcauth_unix.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
svcauth.c net: Move && and || to end of previous line 2009-11-29 16:55:45 -08:00
svcsock.c nfsd: ensure sockets are closed on error 2010-02-28 23:21:51 -05:00
sysctl.c sysctl: Drop & in front of every proc_handler. 2009-11-18 08:37:40 -08:00
timer.c SUNRPC: Add documenting comments in net/sunrpc/timer.c 2009-08-09 15:09:47 -04:00
xdr.c xdr: Add an export for the helper function write_bytes_to_xdr_buf() 2010-05-14 15:09:18 -04:00
xprt.c SUNRPC: Replace jiffies-based metrics with ktime-based metrics 2010-05-14 15:09:33 -04:00
xprtsock.c SUNRPC: RPC metrics and RTT estimator should use same RTT value 2010-05-14 15:09:32 -04:00