- 09 11月, 2009 1 次提交
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由 Corrado Zoccolo 提交于
Cfq has a bug in computation of next_rq, that affects transition between multiple sequential request streams in a single queue (e.g.: two sequential buffered writers of the same priority), causing the alternation between the two streams for a transient period. 8,0 1 18737 0.260400660 5312 D W 141653311 + 256 8,0 1 20839 0.273239461 5400 D W 141653567 + 256 8,0 1 20841 0.276343885 5394 D W 142803919 + 256 8,0 1 20843 0.279490878 5394 D W 141668927 + 256 8,0 1 20845 0.292459993 5400 D W 142804175 + 256 8,0 1 20847 0.295537247 5400 D W 141668671 + 256 8,0 1 20849 0.298656337 5400 D W 142804431 + 256 8,0 1 20851 0.311481148 5394 D W 141668415 + 256 8,0 1 20853 0.314421305 5394 D W 142804687 + 256 8,0 1 20855 0.318960112 5400 D W 142804943 + 256 The fix makes sure that the next_rq is computed from the last dispatched request, and not affected by merging. 8,0 1 37776 4.305161306 0 D W 141738087 + 256 8,0 1 37778 4.308298091 0 D W 141738343 + 256 8,0 1 37780 4.312885190 0 D W 141738599 + 256 8,0 1 37782 4.315933291 0 D W 141738855 + 256 8,0 1 37784 4.319064459 0 D W 141739111 + 256 8,0 1 37786 4.331918431 5672 D W 142803007 + 256 8,0 1 37788 4.334930332 5672 D W 142803263 + 256 8,0 1 37790 4.337902723 5672 D W 142803519 + 256 8,0 1 37792 4.342359774 5672 D W 142803775 + 256 8,0 1 37794 4.345318286 0 D W 142804031 + 256 Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 04 11月, 2009 5 次提交
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由 H Hartley Sweeten 提交于
Quiet sparse noise about symbol's not being declared. Symbol blk_default_cmd_filter is only used locally and should be static. The function blk_scsi_ioctl_init() is a fs_initcall and should also be static. Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
We need to rework this logic post the cooperating cfq_queue merging, for now just get rid of it and Jeff Moyer will fix the fall out. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
We ended up with testing the same condition twice, pretty pointless. Remove that first if. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Shaohua Li 提交于
CFQ has an optimization for cooperated applications. if several io-context have close requests, they will get boost. But the optimization get abused. Considering thread a, b, which work on one file. a reads sectors s, s+2, s+4, ...; b reads sectors s+1, s+3, s +5, ... Both a and b are sequential read, so they can open idle window. a reads a sector s and goes to idle window and wakeup b. b reads sector s+1, since in current implementation, cfq_should_preempt() thinks a and b are cooperators, b will preempt a. b then reads sector s+1 and goes to idle window and wakeup a. for the same reason, a will preempt b and reads s+2. a and b will continue the circle. The circle will be very long, and a and b will occupy whole disk queue. Other applications will nearly have no chance to run. Fix this limiting coop preempt until a queue is scheduled normally again. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Commit a6151c3a inadvertently reversed a preempt condition check, potentially causing a performance regression. Make the meta check correct again. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 02 11月, 2009 1 次提交
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由 Corrado Zoccolo 提交于
Eliminate redundant checks. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 28 10月, 2009 6 次提交
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由 Jens Axboe 提交于
Line breaks and bad brace placement. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
Currently no-idle queues in cfq are not serviced fairly: even if they can only dispatch a small number of requests at a time, they have to compete with idling queues to be serviced, experiencing large latencies. We should notice, instead, that no-idle queues are the ones that would benefit most from having low latency, in fact they are any of: * processes with large think times (e.g. interactive ones like file managers) * seeky (e.g. programs faulting in their code at startup) * or marked as no-idle from upper levels, to improve latencies of those requests. This patch improves the fairness and latency for those queues, by: * separating sync idle, sync no-idle and async queues in separate service_trees, for each priority * service all no-idle queues together * and idling when the last no-idle queue has been serviced, to anticipate for more no-idle work * the timeslices allotted for idle and no-idle service_trees are computed proportionally to the number of processes in each set. Servicing all no-idle queues together should have a performance boost for NCQ-capable drives, without compromising fairness. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
cfq can disable idling for queues in various circumstances. When workloads of different priorities are competing, if the higher priority queue has idling disabled, lower priority queues may steal its disk share. For example, in a scenario with an RT process performing seeky reads vs a BE process performing sequential reads, on an NCQ enabled hardware, with low_latency unset, the RT process will dispatch only the few pending requests every full slice of service for the BE process. The patch solves this issue by always performing idle on the last queue at a given priority class > idle. If the same process, or one that can pre-empt it (so at the same priority or higher), submits a new request within the idle window, the lower priority queue won't dispatch, saving the disk bandwidth for higher priority ones. Note: this doesn't touch the non_rotational + NCQ case (no hardware to test if this is a benefit in that case). Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
We use different service trees for different priority classes. This allows a simplification in the service tree insertion code, that no longer has to consider priority while walking the tree. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
We embed a pointer to the service tree in each queue, to handle multiple service trees easily. Service trees are enriched with a counter. cfq_add_rq_rb is invoked after putting the rq in the fifo, to ensure that all fields in rq are properly initialized. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
When the number of processes performing I/O concurrently increases, a fixed time slice per process will cause large latencies. This patch, if low_latency mode is enabled, will scale the time slice assigned to each process according to a 300ms target latency. In order to keep fairness among processes: * The number of active processes is computed using a special form of running average, that quickly follows sudden increases (to keep latency low), and decrease slowly (to have fairness in spite of rapid decreases of this value). To safeguard sequential bandwidth, we impose a minimum time slice (computed using 2*cfq_slice_idle as base, adjusted according to priority and async-ness). Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 27 10月, 2009 1 次提交
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由 Shaohua Li 提交于
If active queue hasn't enough requests and idle window opens, cfq will not dispatch sufficient requests to hardware. In such situation, current code will zero hw_tag. But this is because cfq doesn't dispatch enough requests instead of hardware queue doesn't work. Don't zero hw_tag in such case. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 26 10月, 2009 4 次提交
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由 Jeff Moyer 提交于
cfq_queues are merged if they are issuing requests within the mean seek distance of one another. This patch detects when the coopearting stops and breaks the queues back up. Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jeff Moyer 提交于
The flag used to indicate that a cfqq was allowed to jump ahead in the scheduling order due to submitting a request close to the queue that just executed. Since closely cooperating queues are now merged, the flag holds little meaning. Change it to indicate that multiple queues were merged. This will later be used to allow the breaking up of merged queues when they are no longer cooperating. Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jeff Moyer 提交于
When cooperating cfq_queues are detected currently, they are allowed to skip ahead in the scheduling order. It is much more efficient to automatically share the cfq_queue data structure between cooperating processes. Performance of the read-test2 benchmark (which is written to emulate the dump(8) utility) went from 12MB/s to 90MB/s on my SATA disk. NFS servers with multiple nfsd threads also saw performance increases. Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jeff Moyer 提交于
async cfq_queue's are already shared between processes within the same priority, and forthcoming patches will change the mapping of cic to sync cfq_queue from 1:1 to 1:N. So, calculate the seekiness of a process based on the cfq_queue instead of the cfq_io_context. Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 24 10月, 2009 1 次提交
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由 Mark McLoughlin 提交于
With 2.6.32-rc5 in a KVM guest using dm and virtio_blk, we see the following errors: end_request: I/O error, dev vda, sector 0 end_request: I/O error, dev vda, sector 0 The errors go away if dm stops submitting empty barriers, by reverting: commit 52b1fd5a Author: Mikulas Patocka <mpatocka@redhat.com> dm: send empty barriers to targets in dm_flush We should silently error all barriers, even empty barriers, on devices like virtio_blk which don't support them. See also: https://bugzilla.redhat.com/514901Signed-off-by: NMark McLoughlin <markmc@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Acked-by: NAlasdair G Kergon <agk@redhat.com> Acked-by: NMikulas Patocka <mpatocka@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 12 10月, 2009 1 次提交
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由 Randy Dunlap 提交于
Fix kernel-doc notation in blk-settings.c::blk_queue_max_discard_sectors(). Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 09 10月, 2009 1 次提交
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由 KOSAKI Motohiro 提交于
elv_iosched_store() ignore the return value of strstrip(). It makes small inconsistent behavior. This patch fixes it. <before> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler bash: echo: write error: Invalid argument <after> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler noop [anticipatory] deadline cfq Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 08 10月, 2009 3 次提交
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由 Corrado Zoccolo 提交于
If the average think time is larger than the remaining time slice for any given queue, don't allow it to idle. A succesful idle also means that we need to dispatch and complete a request, so if we don't even have time left for the idle process, we would overrun the slice in any case. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Saves 16 bytes of text, woohoo. But the more important point is that it makes the code more readable when returning bool for 0/1 cases. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
CFQ enables idle only for processes that think less than the allowed idle time. Since idle time is lower for seeky queues, we should use the correct value in the comparison. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 07 10月, 2009 4 次提交
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由 Jens Axboe 提交于
We should subtract the slice residual from the rb tree key, since a negative residual count indicates that the cfqq overran its slice the last time. Hence we want to add the overrun time, to position it a bit further away in the service tree. Reported-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Makes the whole thing easier to read, cfq_dispatch_requests() was a bit messy before. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Makes it easier to read than the 0. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Nikanth Karthikesan 提交于
Commit a9327cac added seperate read and write statistics of in_flight requests. And exported the number of read and write requests in progress seperately through sysfs. But Corrado Zoccolo <czoccolo@gmail.com> reported getting strange output from "iostat -kx 2". Global values for service time and utilization were garbage. For interval values, utilization was always 100%, and service time is higher than normal. So this was reverted by commit 0f78ab98 The problem was in part_round_stats_single(), I missed the following: if (now == part->stamp) return; - if (part->in_flight) { + if (part_in_flight(part)) { __part_stat_add(cpu, part, time_in_queue, part_in_flight(part) * (now - part->stamp)); __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); With this chunk included, the reported regression gets fixed. Signed-off-by: NNikanth Karthikesan <knikanth@suse.de> -- Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 05 10月, 2009 5 次提交
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由 Jens Axboe 提交于
It was briefly introduced to allow CFQ to to delayed scheduling, but we ended up removing that feature again. So lets kill the function and export, and just switch CFQ back to the normal work schedule since it is now passing in a '0' delay from all call sites. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
The RR service tree is indexed by a key that is relative to current jiffies. This can cause problems on jiffies wraparound. The patch fixes it using time_before comparison, and changing the add_front path to use a relative number, too. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
cfq uses rq->start_time as the fifo indicator, but that field may get modified prior to cfq doing it's fifo list adjustment when a request gets merged with another request. This can cause the fifo list to become unordered. Reported-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
This reverts commit a9327cac. Corrado Zoccolo <czoccolo@gmail.com> reports: "with 2.6.32-rc1 I started getting the following strange output from "iostat -kx 2": Linux 2.6.31bisect (et2) 04/10/2009 _i686_ (2 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 10,70 0,00 3,16 15,75 0,00 70,38 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 18,22 0,00 0,67 0,01 14,77 0,02 43,94 0,01 10,53 39043915,03 2629219,87 sdb 60,89 9,68 50,79 3,04 1724,43 50,52 65,95 0,70 13,06 488437,47 2629219,87 avg-cpu: %user %nice %system %iowait %steal %idle 2,72 0,00 0,74 0,00 0,00 96,53 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 avg-cpu: %user %nice %system %iowait %steal %idle 6,68 0,00 0,99 0,00 0,00 92,33 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 avg-cpu: %user %nice %system %iowait %steal %idle 4,40 0,00 0,73 1,47 0,00 93,40 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 4,00 0,00 3,00 0,00 28,00 18,67 0,06 19,50 333,33 100,00 Global values for service time and utilization are garbage. For interval values, utilization is always 100%, and service time is higher than normal. I bisected it down to: [a9327cac] Seperate read and write statistics of in_flight requests and verified that reverting just that commit indeed solves the issue on 2.6.32-rc1." So until this is debugged, revert the bad commit. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
We cannot delay for the first dispatch of the async queue if it hasn't dispatched at all, since that could present a local user DoS attack vector using an app that just did slow timed sync reads while filling memory. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 04 10月, 2009 3 次提交
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由 Martin K. Petersen 提交于
Not all users of the topology information want to use libblkid. Provide the topology information through bdev ioctls. Also clarify sector size comments for existing BLK ioctls. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
We should use the sysfs modified slice sync value, in case it differs from the default. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Don't think that's necessarily a perfect description of what this option fiddles with, but it's probably better than 'desktop'. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 03 10月, 2009 4 次提交
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由 Jens Axboe 提交于
This slowly ramps up the async queue depth based on the time passed since the sync IO, and doesn't allow async at all until a sync slice period has passed. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Vivek Goyal 提交于
o Do not allow more than max_dispatch requests from an async queue, if some sync request has finished recently. This is in the hope that sync activity is still going on in the system and we might receive a sync request soon. Most likely from a sync queue which finished a request and we did not enable idling on it. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Update Kconfig.iosched entry. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
AS is mostly a subset of CFQ, so there's little point in still providing this separate IO scheduler. Hopefully at some point we can get down to one single IO scheduler again, at least this brings us closer by having only one intelligent IO scheduler. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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