glusterfs.git/xlators/performance/io-threads/src/io-threads.c, branch v3.6.0alpha1

performance/io-threads: Remove code duplication

2014-02-25T02:56:06+00:00

Change-Id: Ic905cc6074c796efce2972857b79ab53700a2de4
BUG: 1065657
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/7010
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

zerofill: Change the type of len argument of glfs_zerofill() to off_t

2013-11-15T07:29:48+00:00

glfs_zerofill() can be potentially called to zero-out entire file and
hence allow for bigger value of length parameter.

Change-Id: I75f1d11af298915049a3f3a7cb3890a2d72fca63
BUG: 1028673
Signed-off-by: Bharata B Rao 
Reviewed-on: http://review.gluster.org/6266
Tested-by: Gluster Build System 
Reviewed-by: M. Mohan Kumar 
Tested-by: M. Mohan Kumar 
Reviewed-by: Anand Avati

glusterfs: zerofill support

2013-11-11T05:25:49+00:00

Add support for a new ZEROFILL fop. Zerofill writes zeroes to a file in
the specified range. This fop will be useful when a whole file needs to
be initialized with zero (could be useful for zero filled VM disk image
provisioning or  during scrubbing of VM disk images).

Client/application can issue this FOP for zeroing out. Gluster server
will zero out required range of bytes ie server offloaded zeroing. In
the absence of this fop,  client/application has to repetitively issue
write (zero) fop to the server, which is very inefficient method because
of the overheads involved in RPC calls  and acknowledgements.

WRITESAME is a  SCSI T10 command that takes a block of data as input and
writes the same data to other blocks and this write is handled
completely within the storage and hence is known as offload . Linux ,now
has support for SCSI WRITESAME command which is exposed to the user in
the form of BLKZEROOUT ioctl.  BD Xlator can exploit BLKZEROOUT ioctl to
implement this fop. Thus zeroing out operations can be completely
offloaded to the storage device , making it highly efficient.

The fop takes two arguments offset and size. It zeroes out 'size' number
of bytes in an opened file starting from 'offset' position.

This patch adds zerofill support to the following areas:
	- libglusterfs
	- io-stats
	- performance/md-cache,open-behind
	- quota
	- cluster/afr,dht,stripe
	- rpc/xdr
	- protocol/client,server
	- io-threads
	- marker
	- storage/posix
	- libgfapi

Client applications can exloit this fop by using glfs_zerofill introduced in
libgfapi.FUSE support to this fop has not been added as there is no system call
for this fop.

Changes from previous version 3:
* Removed redundant memory failure log messages

Changes from previous version 2:
* Rebased and fixed build error

Changes from previous version 1:
* Rebased for latest master

TODO :
     * Add zerofill support to trace xlator
     * Expose zerofill capability as part of gluster volume info

Here is a performance comparison of server offloaded zeofill vs zeroing
out using repeated writes.

[root@llmvm02 remote]# time ./offloaded aakash-test log 20

real	3m34.155s
user	0m0.018s
sys	0m0.040s
[root@llmvm02 remote]# time ./manually aakash-test log 20

real	4m23.043s
user	0m2.197s
sys	0m14.457s
[root@llmvm02 remote]# time ./offloaded aakash-test log 25;

real	4m28.363s
user	0m0.021s
sys	0m0.025s
[root@llmvm02 remote]# time ./manually aakash-test log 25

real	5m34.278s
user	0m2.957s
sys	0m18.808s

The argument log is a file which we want to set for logging purpose and
the third argument is size in GB .

As we can see there is a performance improvement of around 20% with this
fop.

Change-Id: I081159f5f7edde0ddb78169fb4c21c776ec91a18
BUG: 1028673
Signed-off-by: Aakash Lal Das 
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/5327
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

core: block unused signals in created threads

2013-09-25T08:33:16+00:00

Block all signal except those which are set for explicit handling
in glusterfs_signals_setup(). Since thread spawning code in
libglusterfs and xlators can get called from application threads
when used through libgfapi, it is necessary to do this blocking.

Change-Id: Ia320f80521a83d2edcda50b9ad414583a0175281
BUG: 1011662
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/5995
Tested-by: Gluster Build System 
Reviewed-by: Amar Tumballi 
Reviewed-by: Vijay Bellur

performance/io-threads: fix potential use after free crash

2013-08-02T04:03:17+00:00

do_iot_schedule() enqueues the stub and kicks the worker thread.
The stub is eventually destroyed after it has been resumed and thus
unsafe to access after being enqueued.

Though likely difficult to reproduce in a real deployment, a crash
is reproducible by running a smallfile benchmark on a replica 2
volume on a single vm. Reorder the debug log message prior to the
do_iot_schedule() call to avoid the crash.

BUG: 989579
Change-Id: Ifc6502c02ae455c959a90ff1ca62a690e31ceafb
Signed-off-by: Brian Foster 
Reviewed-on: http://review.gluster.org/5418
Reviewed-by: Santosh Pradhan 
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

glusterfs: discard (hole punch) support

2013-06-13T21:37:43+00:00

Add support for the DISCARD file operation. Discard punches a hole
in a file in the provided range. Block de-allocation is implemented
via fallocate() (as requested via fuse and passed on to the brick
fs) but a separate fop is created within gluster to emphasize the
fact that discard changes file data (the discarded region is
replaced with zeroes) and must invalidate caches where appropriate.

BUG: 963678
Change-Id: I34633a0bfff2187afeab4292a15f3cc9adf261af
Signed-off-by: Brian Foster 
Reviewed-on: http://review.gluster.org/5090
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

gluster: add fallocate fop support

2013-06-13T21:37:21+00:00

Implement support for the fallocate file operation. fallocate
allocates blocks for a particular inode such that future writes
to the associated region of the file are guaranteed not to fail
with ENOSPC.

This patch adds fallocate support to the following areas:

	- libglusterfs
	- mount/fuse
	- io-stats
	- performance/md-cache,open-behind
	- quota
	- cluster/afr,dht,stripe
	- rpc/xdr
	- protocol/client,server
	- io-threads
	- marker
	- storage/posix
	- libgfapi

BUG: 949242
Change-Id: Ice8e61351f9d6115c5df68768bc844abbf0ce8bd
Signed-off-by: Brian Foster 
Reviewed-on: http://review.gluster.org/4969
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

performance/io-threads: Fix range-check for least-rate-limit

2013-03-21T07:05:19+00:00

The issue could be fixed with .validate=GF_OPT_VALIDATE_MIN. But
adding max value is more robust.

Change-Id: Ia69c6f86855dbd34a26e20391e77bfa0f796a200
BUG: 923573
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/4698
Reviewed-by: Brian Foster 
Reviewed-by: Jeff Darcy 
Tested-by: Gluster Build System

core: fixes for gcc's '-pedantic' flag build

2013-01-22T06:17:36+00:00

* warnings on 'void *' arguments
* warnings on empty initializations
* warnings on empty array (array[0])

Change-Id: Iae440f54cbd59580eb69f3ecaed5a9926c0edf95
BUG: 875913
Signed-off-by: Avra Sengupta 
Reviewed-on: http://review.gluster.org/4219
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

perf/io-threads: least-rate-limit least priority throttling

2012-11-21T21:49:47+00:00

The 'least-rate-limit' io-threads translator option enables
throttling of least priority operations. This is initially intended
as a debug/diagnostic tool for users who might experience
overloaded servers via background activity (i.e., self-heal).

least-rate-limit defines the maximum number of least priority
operations the io-threads translator will dequeue in one second.
If the specified rate limit is met, the worker threads sleep for
the minimal amount of time before the next least priority operation
becomes available (or until a new request arrives).

The requests/second metric is generic and relative to a variety of
factors involved with a background operation (server, storage,
etc.). The most recent measured rate ("cached least rate") is added
to the io-threads state dump content (kill -USR1) to serve as a
reference point to throttle background activity under particular
conditions.

Change-Id: I80f2282992137d57b1becaa5c6ae3858c066862a
BUG: 853680
Signed-off-by: Brian Foster 
Reviewed-on: http://review.gluster.org/4119
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati