- 02 4月, 2010 1 次提交
-
-
由 Divyesh Shah 提交于
that info at request dispatch with other stats now. This patch removes the existing support for accounting sectors for a blkio_group. This will be added back differently in the next two patches. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 25 3月, 2010 2 次提交
-
-
由 Divyesh Shah 提交于
Even if they are found to be co-operating. The prio_trees do not have any IDLE cfqqs on them. cfq_close_cooperator() is called from cfq_select_queue() and cfq_completed_request(). The latter ensures that the close cooperator code does not get invoked if the current cfqq is of class IDLE but the former doesn't seem to have any such checks. So an IDLE cfqq may get merged with a BE cfqq from the same group which should be avoided. Signed-off-by: Divyesh Shah<dpshah@google.com> Acked-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Divyesh Shah 提交于
These have helped us debug some issues we've noticed in earlier IO controller versions and should be useful now as well. The extra logging covers: - idling behavior. Since there are so many conditions based on which we decide to idle or not, this patch adds a log message for some conditions that we've found useful. - workload slices and current prio and workload type Changelog from v1: o moved log message from cfq_set_active_queue() to __cfq_set_active_queue() o changed queue_count to st->count Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 19 3月, 2010 1 次提交
-
-
由 Shaohua Li 提交于
Alex Shi reported a kbuild regression which is about 10% performance lost. He bisected to this commit: 3dde36dd. The reason is cfqq_close() can't find close cooperator. Restoring cfq_rq_close()'s threshold to original value makes the regression go away. Since for_preempt parameter isn't used anymore, this patch deletes it. Reported-by: NAlex Shi <alex.shi@intel.com> Signed-off-by: NShaohua Li <shaohua.li@intel.com> Acked-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 01 3月, 2010 5 次提交
-
-
由 Richard Kennedy 提交于
Reorder cfq_rb_root to remove 8 bytes of padding on 64 bit builds. Consequently removing 56 bytes from cfq_group and 64 bytes from cfq_data. Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Shaohua Li 提交于
Currently a queue can only dispatch up to 4 requests if there are other queues. This isn't optimal, device can handle more requests, for example, AHCI can handle 31 requests. I can understand the limit is for fairness, but we could do a tweak: if the queue still has a lot of slice left, sounds we could ignore the limit. Test shows this boost my workload (two thread randread of a SSD) from 78m/s to 100m/s. Thanks for suggestions from Corrado and Vivek for the patch. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Corrado Zoccolo 提交于
Counters for requests "in flight" and "in driver" are used asymmetrically in cfq_may_dispatch, and have slightly different meaning. We split the rq_in_flight counter (was sync_flight) to count both sync and async requests, in order to use this one, which is more accurate in some corner cases. The rq_in_driver counter is coalesced, since individual sync/async counts are not used any more. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Corrado Zoccolo 提交于
CFQ currently applies the same logic of detecting seeky queues and grouping them together for rotational disks as well as SSDs. For SSDs, the time to complete a request doesn't depend on the request location, but only on the size. This patch therefore changes the criterion to group queues by request size in case of SSDs, in order to achieve better fairness. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Corrado Zoccolo 提交于
Current seeky detection is based on average seek lenght. This is suboptimal, since the average will not distinguish between: * a process doing medium sized seeks * a process doing some sequential requests interleaved with larger seeks and even a medium seek can take lot of time, if the requested sector happens to be behind the disk head in the rotation (50% probability). Therefore, we change the seeky queue detection to work as follows: * each request can be classified as sequential if it is very close to the current head position, i.e. it is likely in the disk cache (disks usually read more data than requested, and put it in cache for subsequent reads). Otherwise, the request is classified as seeky. * an history window of the last 32 requests is kept, storing the classification result. * A queue is marked as seeky if more than 1/8 of the last 32 requests were seeky. This patch fixes a regression reported by Yanmin, on mmap 64k random reads. Reported-by: NYanmin Zhang <yanmin_zhang@linux.intel.com> Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 26 2月, 2010 1 次提交
-
-
由 Gui Jianfeng 提交于
There's no need to take css reference here, for the caller has already called rcu_read_lock() to prevent cgroup from being removed. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Reviewed-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 22 2月, 2010 1 次提交
-
-
由 Richard Kennedy 提交于
This removes 8 bytes of padding from struct cfq_queue on 64 bit builds, shrinking it's size to 256 bytes, so fitting into 1 fewer cachelines and allowing 1 more object/slab in it's kmem_cache. Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk> Reviewed-by: NJeff Moyer <jmoyer@redhat.com> ---- patch against 2.6.33-rc8 tested on x86_64 AMDX2 Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 05 2月, 2010 1 次提交
-
-
由 Shaohua Li 提交于
Currently we split seeky coop queues after 1s, which is too big. Below patch marks seeky coop queue split_coop flag after one slice. After that, if new requests come in, the queues will be splitted. Patch is suggested by Corrado. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Reviewed-by: NCorrado Zoccolo <czoccolo@gmail.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 03 2月, 2010 1 次提交
-
-
由 Vivek Goyal 提交于
Few weeks back, Shaohua Li had posted similar patch. I am reposting it with more test results. This patch does two things. - Do not idle on async queues. - It also changes the write queue depth CFQ drives (cfq_may_dispatch()). Currently, we seem to driving queue depth of 1 always for WRITES. This is true even if there is only one write queue in the system and all the logic of infinite queue depth in case of single busy queue as well as slowly increasing queue depth based on last delayed sync request does not seem to be kicking in at all. This patch will allow deeper WRITE queue depths (subjected to the other WRITE queue depth contstraints like cfq_quantum and last delayed sync request). Shaohua Li had reported getting more out of his SSD. For me, I have got one Lun exported from an HP EVA and when pure buffered writes are on, I can get more out of the system. Following are test results of pure buffered writes (with end_fsync=1) with vanilla and patched kernel. These results are average of 3 sets of run with increasing number of threads. AVERAGE[bufwfs][vanilla] ------- job Set NR ReadBW(KB/s) MaxClat(us) WriteBW(KB/s) MaxClat(us) --- --- -- ------------ ----------- ------------- ----------- bufwfs 3 1 0 0 95349 474141 bufwfs 3 2 0 0 100282 806926 bufwfs 3 4 0 0 109989 2.7301e+06 bufwfs 3 8 0 0 116642 3762231 bufwfs 3 16 0 0 118230 6902970 AVERAGE[bufwfs] [patched kernel] ------- bufwfs 3 1 0 0 270722 404352 bufwfs 3 2 0 0 206770 1.06552e+06 bufwfs 3 4 0 0 195277 1.62283e+06 bufwfs 3 8 0 0 260960 2.62979e+06 bufwfs 3 16 0 0 299260 1.70731e+06 I also ran buffered writes along with some sequential reads and some buffered reads going on in the system on a SATA disk because the potential risk could be that we should not be driving queue depth higher in presence of sync IO going to keep the max clat low. With some random and sequential reads going on in the system on one SATA disk I did not see any significant increase in max clat. So it looks like other WRITE queue depth control logic is doing its job. Here are the results. AVERAGE[brr, bsr, bufw together] [vanilla] ------- job Set NR ReadBW(KB/s) MaxClat(us) WriteBW(KB/s) MaxClat(us) --- --- -- ------------ ----------- ------------- ----------- brr 3 1 850 546345 0 0 bsr 3 1 14650 729543 0 0 bufw 3 1 0 0 23908 8274517 brr 3 2 981.333 579395 0 0 bsr 3 2 14149.7 1175689 0 0 bufw 3 2 0 0 21921 1.28108e+07 brr 3 4 898.333 1.75527e+06 0 0 bsr 3 4 12230.7 1.40072e+06 0 0 bufw 3 4 0 0 19722.3 2.4901e+07 brr 3 8 900 3160594 0 0 bsr 3 8 9282.33 1.91314e+06 0 0 bufw 3 8 0 0 18789.3 23890622 AVERAGE[brr, bsr, bufw mixed] [patched kernel] ------- job Set NR ReadBW(KB/s) MaxClat(us) WriteBW(KB/s) MaxClat(us) --- --- -- ------------ ----------- ------------- ----------- brr 3 1 837 417973 0 0 bsr 3 1 14357.7 591275 0 0 bufw 3 1 0 0 24869.7 8910662 brr 3 2 1038.33 543434 0 0 bsr 3 2 13351.3 1205858 0 0 bufw 3 2 0 0 18626.3 13280370 brr 3 4 913 1.86861e+06 0 0 bsr 3 4 12652.3 1430974 0 0 bufw 3 4 0 0 15343.3 2.81305e+07 brr 3 8 890 2.92695e+06 0 0 bsr 3 8 9635.33 1.90244e+06 0 0 bufw 3 8 0 0 17200.3 24424392 So looks like it might make sense to include this patch. Thanks Vivek Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 11 1月, 2010 1 次提交
-
-
由 Divyesh Shah 提交于
In cfq_should_preempt(), we currently allow some cases where a non-RT request can preempt an ongoing RT cfqq timeslice. This should not happen. Examples include: o A sync_noidle wl type non-RT request pre-empting a sync_noidle wl type cfqq on which we are idling. o Once we have per-cgroup async queues, a non-RT sync request pre-empting a RT async cfqq. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 28 12月, 2009 1 次提交
-
-
由 Shaohua Li 提交于
seek_mean could be very big sometimes, using it as close criteria is meaningless as this doen't improve any performance. So if it's big, let's fallback to default value. Reviewed-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Shaohua Li<shaohua.li@intel.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 18 12月, 2009 3 次提交
-
-
由 Vivek Goyal 提交于
o CFQ now internally divides cfq queues in therr workload categories. sync-idle, sync-noidle and async. Which workload to run depends primarily on rb_key offset across three service trees. Which is a combination of mulitiple things including what time queue got queued on the service tree. There is one exception though. That is if we switched the prio class, say we served some RT tasks and again started serving BE class, then with-in BE class we always started with sync-noidle workload irrespective of rb_key offset in service trees. This can provide better latencies for sync-noidle workload in the presence of RT tasks. o This patch gets rid of that exception and which workload to run with-in class always depends on lowest rb_key across service trees. The reason being that now we have multiple BE class groups and if we always switch to sync-noidle workload with-in group, we can potentially starve a sync-idle workload with-in group. Same is true for async workload which will be in root group. Also the workload-switching with-in group will become very unpredictable as it now depends whether some RT workload was running in the system or not. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Acked-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o Currently code does not seem to be using cfqd->nr_groups. Get rid of it. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o allow_merge() already checks if submitting task is pointing to same cfqq as rq has been queued in. If everything is fine, we should not be having a task in one cgroup and having a pointer to cfqq in other cgroup. Well I guess in some situations it can happen and that is, when a random IO queue has been moved into root cgroup for group_isolation=0. In this case, tasks's cgroup/group is different from where actually cfqq is, but this is intentional and in this case merging should be allowed. The second situation is where due to close cooperator patches, multiple processes can be sharing a cfqq. If everything implemented right, we should not end up in a situation where tasks from different processes in different groups are sharing the same cfqq as we allow merging of cooperating queues only if they are in same group. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 15 12月, 2009 1 次提交
-
-
由 Gui Jianfeng 提交于
When a group is resumed, if it doesn't have workload slice left, we should set workload_expires as expired. Otherwise, we might start from where we left in previous group by error. Thanks the idea from Corrado. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 11 12月, 2009 1 次提交
-
-
由 Vivek Goyal 提交于
I think my previous patch introduced a bug which can lead to CFQ hitting BUG_ON(). The offending commit in for-2.6.33 branch is. commit 7667aa06 Author: Vivek Goyal <vgoyal@redhat.com> Date: Tue Dec 8 17:52:58 2009 -0500 cfq-iosched: Take care of corner cases of group losing share due to deletion While doing some stress testing on my box, I enountered following. login: [ 3165.148841] BUG: scheduling while atomic: swapper/0/0x10000100 [ 3165.149821] Modules linked in: cfq_iosched dm_multipath qla2xxx igb scsi_transport_fc dm_snapshot [last unloaded: scsi_wait_scan] [ 3165.149821] Pid: 0, comm: swapper Not tainted 2.6.32-block-for-33-merged-new #3 [ 3165.149821] Call Trace: [ 3165.149821] <IRQ> [<ffffffff8103fab8>] __schedule_bug+0x5c/0x60 [ 3165.149821] [<ffffffff8103afd7>] ? __wake_up+0x44/0x4d [ 3165.149821] [<ffffffff8153a979>] schedule+0xe3/0x7bc [ 3165.149821] [<ffffffff8103a796>] ? cpumask_next+0x1d/0x1f [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff810422d8>] __cond_resched+0x2a/0x35 [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff8153b1ee>] _cond_resched+0x2c/0x37 [ 3165.149821] [<ffffffff8100e2db>] is_valid_bugaddr+0x16/0x2f [ 3165.149821] [<ffffffff811e4161>] report_bug+0x18/0xac [ 3165.149821] [<ffffffff8100f1fc>] die+0x39/0x63 [ 3165.149821] [<ffffffff8153cde1>] do_trap+0x11a/0x129 [ 3165.149821] [<ffffffff8100d470>] do_invalid_op+0x96/0x9f [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff81034b4d>] ? enqueue_task+0x5c/0x67 [ 3165.149821] [<ffffffff8103ae83>] ? task_rq_unlock+0x11/0x13 [ 3165.149821] [<ffffffff81041aae>] ? try_to_wake_up+0x292/0x2a4 [ 3165.149821] [<ffffffff8100c935>] invalid_op+0x15/0x20 [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f [ 3165.149821] [<ffffffff811d8c2a>] blk_peek_request+0x191/0x1a7 [ 3165.149821] [<ffffffff811e5b8d>] ? kobject_get+0x1a/0x21 [ 3165.149821] [<ffffffff812c8d4c>] scsi_request_fn+0x82/0x3df [ 3165.149821] [<ffffffff8110b2de>] ? bio_fs_destructor+0x15/0x17 [ 3165.149821] [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f [ 3165.149821] [<ffffffff811d931f>] __blk_run_queue+0x42/0x71 [ 3165.149821] [<ffffffff811d9403>] blk_run_queue+0x26/0x3a [ 3165.149821] [<ffffffff812c8761>] scsi_run_queue+0x2de/0x375 [ 3165.149821] [<ffffffff812b60ac>] ? put_device+0x17/0x19 [ 3165.149821] [<ffffffff812c92d7>] scsi_next_command+0x3b/0x4b [ 3165.149821] [<ffffffff812c9b9f>] scsi_io_completion+0x1c9/0x3f5 [ 3165.149821] [<ffffffff812c3c36>] scsi_finish_command+0xb5/0xbe I think I have hit following BUG_ON() in cfq_dispatch_request(). BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); Please find attached the patch to fix it. I have done some stress testing with it and have not seen it happening again. o We should wait on a queue even after slice expiry only if it is empty. If queue is not empty then continue to expire it. o If we decide to keep the queue then make cfqq=NULL. Otherwise select_queue() will return a valid cfqq and cfq_dispatch_request() can hit following BUG_ON(). BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)) Reviewed-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 10 12月, 2009 2 次提交
-
-
由 Gui Jianfeng 提交于
Remove wait_request flag when idle time is being deleted, otherwise it'll hit this path every time when a request is enqueued. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Corrado Zoccolo 提交于
Added a comment to explain the initialization of last_delayed_sync. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 09 12月, 2009 4 次提交
-
-
由 Vivek Goyal 提交于
If there is a sequential reader running in a group, we wait for next request to come in that group after slice expiry and once new request is in, we expire the queue. Otherwise we delete the group from service tree and group looses its fair share. So far I was marking a queue as wait_busy if it had consumed its slice and it was last queue in the group. But this condition did not cover following two cases. 1.If a request completed and slice has not expired yet. Next request comes in and is dispatched to disk. Now select_queue() hits and slice has expired. This group will be deleted. Because request is still in the disk, this queue will never get a chance to wait_busy. 2.If request completed and slice has not expired yet. Before next request comes in (delay due to think time), select_queue() hits and expires the queue hence group. This queue never got a chance to wait busy. Gui was hitting the boundary condition 1 and not getting fairness numbers proportional to weight. This patch puts the checks for above two conditions and improves the fairness numbers for sequential workload on rotational media. Check in select_queue() takes care of case 1 and additional check in should_wait_busy() takes care of case 2. Reported-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o Get rid of wait_busy_done flag. This flag only tells we were doing wait busy on a queue and that queue got request so expire it. That information can easily be obtained by (cfq_cfqq_wait_busy() && queue_is_not_empty). So remove this flag and keep code simple. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Gui Jianfeng 提交于
It doesn't make any sense to try to find out a close cooperating queue if current cfqq is the only one in the group. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Corrado Zoccolo 提交于
The introduction of ramp-up formula for async queue depths has slowed down dirty page reclaim, by reducing async write performance. This patch makes sure the formula kicks in only when sync request was recently delayed. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 08 12月, 2009 1 次提交
-
-
由 Vivek Goyal 提交于
Fix a crash during boot reported by Jeff Moyer. Fix the issue of accessing cfqq after freeing it. Reported-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <axboe@carl.(none)>
-
- 06 12月, 2009 1 次提交
-
-
由 Jens Axboe 提交于
After the merge of the IO controller patches, booting on my megaraid box ran much slower. Vivek Goyal traced it down to megaraid discovery creating tons of devices, each suffering a grace period when they later kill that queue (if no device is found). So lets use call_rcu() to batch these deferred frees, instead of taking the grace period hit for each one. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
- 04 12月, 2009 12 次提交
-
-
由 Vivek Goyal 提交于
o One of the goals of block IO controller is that it should be able to support mulitple io control policies, some of which be operational at higher level in storage hierarchy. o To begin with, we had one io controlling policy implemented by CFQ, and I hard coded the CFQ functions called by blkio. This created issues when CFQ is compiled as module. o This patch implements a basic dynamic io controlling policy registration functionality in blkio. This is similar to elevator functionality where ioschedulers register the functions dynamically. o Now in future, when more IO controlling policies are implemented, these can dynakically register with block IO controller. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o blkio controller is inside the kernel and cfq makes use of interfaces exported by blkio. CFQ can be a module too, hence export symbols used by CFQ. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Shaohua Li 提交于
cfq_arm_slice_timer() has logic to disable idle window for SSD device. The same thing should be done at cfq_select_queue() too, otherwise we will still see idle window. This makes the nonrot check logic consistent in cfq. Tests in a intel SSD with low_latency knob close, below patch can triple disk thoughput for muti-thread sequential read. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Jens Axboe 提交于
They should not be declared inside some other file that's not related to CFQ. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o rq_noidle() is supposed to tell cfq that do not expect a request after this one, hence don't idle. But this does not seem to work very well. For example for direct random readers, rq_noidle = 1 but there is next request coming after this. Not idling, leads to a group not getting its share even if group_isolation=1. o The right solution for this issue is to scan the higher layers and set right flag (WRITE_SYNC or WRITE_ODIRECT). For the time being, this single line fix helps. This should not have any significant impact when we are not using cgroups. I will later figure out IO paths in higher layer and fix it. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o If a group is running only a random reader, then it will not have enough traffic to keep disk busy and we will reduce overall throughput. This should result in better latencies for random reader though. If we don't idle on random reader service tree, then this random reader will experience large latencies if there are other groups present in system with sequential readers running in these. o One solution suggested by corrado is that by default keep the random readers or sync-noidle workload in root group so that during one dispatch round we idle only once on sync-noidle tree. This means that all the sync-idle workload queues will be in their respective group and we will see service differentiation in those but not on sync-noidle workload. o Provide a tunable group_isolation. If set, this will make sure that even sync-noidle queues go in their respective group and we wait on these. This provides stronger isolation between groups but at the expense of throughput if group does not have enough traffic to keep the disk busy. o By default group_isolation = 0 Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o Async queues are not per group. Instead these are system wide and maintained in root group. Hence their workload slice length should be calculated based on total number of queues in the system and not just queues in the root group. o As root group's default weight is 1000, make sure to charge async queue more in terms of vtime so that it does not get more time on disk because root group has higher weight. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o If a queue consumes its slice and then gets deleted from service tree, its associated group will also get deleted from service tree if this was the only queue in the group. That will make group loose its share. o For the queues on which we have idling on and if these have used their slice, wait a bit for these queues to get backlogged again and then expire these queues so that group does not loose its share. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o Propagate blkio cgroup weight updation to associated cfq groups. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o If a task changes cgroup, drop reference to the cfqq associated with io context and set cfqq pointer stored in ioc to NULL so that upon next request arrival we will allocate a new queue in new group. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o Do not allow following three operations across groups for isolation. - selection of co-operating queues - preemtpions across groups - request merging across groups. o Async queues are currently global and not per group. Allow preemption of an async queue if a sync queue in other group gets backlogged. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-
由 Vivek Goyal 提交于
o Export disk time and sector used by a group to user space through cgroup interface. o Also export a "dequeue" interface to cgroup which keeps track of how many a times a group was deleted from service tree. Helps in debugging. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
-