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SubjectRe: [PATCH 0/8] block, bfq: extend bfq to support multi-actuator drives
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Date


> Il giorno 28 set 2022, alle ore 03:02, Rory Chen <rory.c.chen@seagate.com> ha scritto:
>
> Hi Arie,
>
> I have no experience to submit the change into kernel. Can Paolo or other maintainers help submit?
>
>

Hi Rory,
the problem here is that your change simply switches off the warning
in BFQ, but the offending sector number is still produced by
bio_end_sector. What we need here is some feedback by Damien or Jens.
Maybe they are not following this thread. I'll try to get their
attention by creating a new thread on the topic. Cross your fingers :)

Thanks,
Paolo

> Seagate Internal
>
> -----Original Message-----
> From: Arie van der Hoeven <arie.vanderhoeven@seagate.com>
> Sent: Wednesday, September 28, 2022 12:59 AM
> To: Rory Chen <rory.c.chen@seagate.com>; Paolo Valente <paolo.valente@linaro.org>
> Cc: Tyler Erickson <tyler.erickson@seagate.com>; Muhammad Ahmad <muhammad.ahmad@seagate.com>; linux-block@vger.kernel.org; linux-kernel@vger.kernel.org; Jan Kara <jack@suse.cz>; andrea.righi@canonical.com; glen.valante@linaro.org; axboe@kernel.dk; Michael English <michael.english@seagate.com>; Andrew Ring <andrew.ring@seagate.com>; Varun Boddu <varunreddy.boddu@seagate.com>; Damien Le Moal <damien.lemoal@wdc.com>
> Subject: Re: [PATCH 0/8] block, bfq: extend bfq to support multi-actuator drives
>
> Chiming in as we have customers who are having very good results with these BFQ patches and are planning to pilot NAS solutions in early 2023. This bug is not a blocker for us, but we do need the BFQ patches included in Linux 6.0.
>
> Rory can you submit your changes or is it the maintainer's responsibility?
>
> Regards, --Arie
>
>
> From: Rory Chen <mailto:rory.c.chen@seagate.com>
> Sent: Thursday, September 8, 2022 4:34 AM
> To: Paolo Valente <mailto:paolo.valente@linaro.org>
> Cc: Tyler Erickson <mailto:tyler.erickson@seagate.com>; Arie van der Hoeven <mailto:arie.vanderhoeven@seagate.com>; Muhammad Ahmad <mailto:muhammad.ahmad@seagate.com>; mailto:linux-block@vger.kernel.org <mailto:linux-block@vger.kernel.org>; mailto:linux-kernel@vger.kernel.org <mailto:linux-kernel@vger.kernel.org>; Jan Kara <mailto:jack@suse.cz>; mailto:andrea.righi@canonical.com <mailto:andrea.righi@canonical.com>; mailto:glen.valante@linaro.org <mailto:glen.valante@linaro.org>; mailto:axboe@kernel.dk <mailto:axboe@kernel.dk>; Michael English <mailto:michael.english@seagate.com>; Andrew Ring <mailto:andrew.ring@seagate.com>; Varun Boddu <mailto:varunreddy.boddu@seagate.com>; Damien Le Moal <mailto:damien.lemoal@wdc.com>
> Subject: Re: [PATCH 0/8] block, bfq: extend bfq to support multi-actuator drives
>
>
> Oops, I attach wrong code change. Here's the right change made by me.
>
> < if (end >= iar->sector + 1 && end < iar->sector + iar->nr_sectors + 1) //Changed code
>> if (end >= iar->sector && end < iar->sector +
>> iar->nr_sectors) // Original code
>
> Unfortunately, the crash is still existing and I can't find any clue from /var/log/messages
>
>
>
> From: Paolo Valente <mailto:paolo.valente@linaro.org>
> Sent: Thursday, September 8, 2022 6:54 PM
> To: Rory Chen <mailto:rory.c.chen@seagate.com>
> Cc: Tyler Erickson <mailto:tyler.erickson@seagate.com>; Arie van der Hoeven <mailto:arie.vanderhoeven@seagate.com>; Muhammad Ahmad <mailto:muhammad.ahmad@seagate.com>; mailto:linux-block@vger.kernel.org <mailto:linux-block@vger.kernel.org>; mailto:linux-kernel@vger.kernel.org <mailto:linux-kernel@vger.kernel.org>; Jan Kara <mailto:jack@suse.cz>; mailto:andrea.righi@canonical.com <mailto:andrea.righi@canonical.com>; mailto:glen.valante@linaro.org <mailto:glen.valante@linaro.org>; mailto:axboe@kernel.dk <mailto:axboe@kernel.dk>; Michael English <mailto:michael.english@seagate.com>; Andrew Ring <mailto:andrew.ring@seagate.com>; Varun Boddu <mailto:varunreddy.boddu@seagate.com>; Damien Le Moal <mailto:damien.lemoal@wdc.com>
> Subject: Re: [PATCH 0/8] block, bfq: extend bfq to support multi-actuator drives
>
>
> This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email.
>
>
>> Il giorno 8 set 2022, alle ore 04:46, Rory Chen <mailto:rory.c.chen@seagate.com> ha scritto:
>>
>> I change the comparison condition and it can eliminate the warning.
>
> Yep. The crash you reported also goes away?
>
>> < if (end >= iar->sector + 1 && end < iar->sector + iar->nr_sectors + 1)
>>> if (end >= iar->sector && end < iar->sector +
>>> iar->nr_sectors)
>>
>> I don't know if this change is appropriate
>
> Unfortunately your change conflicts with the standard code, taken from the original patches on access ranges [1]. I've CCed Damien, the author of this patch series.
>
> [1] https://secure-web.cisco.com/12uvPqOwOjHJPiVGM6hJ7791jpWxxy8My3bFD1oA0pNh9m0W778f8IM7HPxjRUL8-94N0gKahHwtK-sEv1Tgk2Oo4H9GTAlLoml_uWF6BGktvDAlDp-zdNQUzCL7y1OCz_MJMaNlS5h0iwsE3q9m7tJsCFUWW0YEgcJE6LRTrZDQpFJhG3pGCLFgoPIuKa3o8B136dJoQvEtek7ZOQFKqesuZKbu4lvM4ds0HOLs5TIgJR_mSJ8UmhP5_M3a1CaDxdDzQ784H3EydkRN9a6v9-Oogo-wYUqS8fRq35rUyw1t2IblmgJzr6aoGazZsJHxBXPjpxA9DSEQqUtH7oT5RGM4qxLpEmYjgyzpJUZqhUCSXye7-lCTIQIB-SGzRuZDVbIqK5tZd3F_YK9LcAN0iVH_qfBM4zRe_4w4h5ikJdhc/https%3A%2F%2Flwn.net%2Fml%2Flinux-block%2F20210909023545.1101672-2-damien.lemoal%40wdc.com%2F
>
> Thanks,
> Paolo
>
>> but bio_end_sector deducting 1 said by Tyler seems to make sense.
>>
>> From: Paolo Valente <mailto:paolo.valente@linaro.org>
>> Sent: Thursday, August 25, 2022 10:45 PM
>> To: Tyler Erickson <mailto:tyler.erickson@seagate.com>
>> Cc: Rory Chen <mailto:rory.c.chen@seagate.com>; Arie van der Hoeven
>> <mailto:arie.vanderhoeven@seagate.com>; Muhammad Ahmad
>> <mailto:muhammad.ahmad@seagate.com>; mailto:linux-block@vger.kernel.org
>> <mailto:linux-block@vger.kernel.org>; mailto:linux-kernel@vger.kernel.org
>> <mailto:linux-kernel@vger.kernel.org>; Jan Kara <mailto:jack@suse.cz>;
>> mailto:andrea.righi@canonical.com <mailto:andrea.righi@canonical.com>;
>> mailto:glen.valante@linaro.org <mailto:glen.valante@linaro.org>; mailto:axboe@kernel.dk
>> <mailto:axboe@kernel.dk>; Michael English <mailto:michael.english@seagate.com>;
>> Andrew Ring <mailto:andrew.ring@seagate.com>; Varun Boddu
>> <mailto:varunreddy.boddu@seagate.com>
>> Subject: Re: [PATCH 0/8] block, bfq: extend bfq to support
>> multi-actuator drives
>>
>>
>> This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email.
>>
>>
>> Hi
>>
>>> Il giorno 18 ago 2022, alle ore 17:40, Tyler Erickson <mailto:tyler.erickson@seagate.com> ha scritto:
>>>
>>> The libata layer is reporting correctly after the changes I submitted.
>>>
>>> The drive reports the actuator ranges as a starting LBA and a count of LBAs for the range.
>>> If the code reading the reported values simply does startingLBA + range, this is an incorrect ending LBA for that actuator. This is because LBAs are zero indexed and this simple addition is not taking that into account.
>>> The proper way to get the endingLBA is startingLBA + range - 1 to get the last LBA value for where to issue a final IO read/write to account for LBA values starting at zero rather than one.
>>>
>>> Here is an example from the output in SeaChest/openSeaChest:
>>> ====Concurrent Positioning Ranges====
>>>
>>> Range# #Elements Lowest LBA # of LBAs
>>> 0 1 0 17578328064
>>> 1 1 17578328064 17578328064
>>>
>>> If using the incorrect formula to get the final LBA for actuator 0, you would get 17578328064, but this is the starting LBA reported by the drive for actuator 1.
>>> So to be consistent for all ranges, the final LBA for a given actuator should be calculated as starting LBA + range - 1.
>>>
>>
>> Ok
>>
>>> I had reached out to Seagate's T10 and T13 representatives for clarification and verification and this is most likely what is causing the error is a missing - 1 somewhere after getting the information reported by the device. They agreed that the reporting from the drive and the SCSI to ATA translation is correct.
>>>
>>> I'm not sure where this is being read and calculated, but it is not an error in the low-level libata or sd level of the kernel. It may be in bfq, or it may be in some other place after the sd layer.
>>
>> This apparent mistake is in the macro bio_end_sector (defined in
>> include/linux/bio.h), which seems to be translated as sector+size.
>> Jens, can you shed a light on this point?
>>
>> Thanks,
>> Paolo
>>
>>> I know there were some additions to read this and report it up the stack, but I did not think those were wrong as they seemed to pass the drive reported information up the stack.
>>>
>>> Tyler Erickson
>>> Seagate Technology
>>>
>>>
>>> Seagate Internal
>>>
>>> -----Original Message-----
>>> From: Rory Chen <mailto:rory.c.chen@seagate.com>
>>> Sent: Wednesday, August 10, 2022 6:59 AM
>>> To: Paolo Valente <mailto:paolo.valente@linaro.org>
>>> Cc: Arie van der Hoeven <mailto:arie.vanderhoeven@seagate.com>; Muhammad
>>> Ahmad <mailto:muhammad.ahmad@seagate.com>; mailto:linux-block@vger.kernel.org;
>>> mailto:linux-kernel@vger.kernel.org; Jan Kara <mailto:jack@suse.cz>;
>>> mailto:andrea.righi@canonical.com; mailto:glen.valante@linaro.org; mailto:axboe@kernel.dk;
>>> Tyler Erickson <mailto:tyler.erickson@seagate.com>; Michael English
>>> <mailto:michael.english@seagate.com>; Andrew Ring <mailto:andrew.ring@seagate.com>;
>>> Varun Boddu <mailto:varunreddy.boddu@seagate.com>
>>> Subject: Re: [PATCH 0/8] block, bfq: extend bfq to support
>>> multi-actuator drives
>>>
>>> The block trace shows the start sector is 35156656120 and transfer length is 8 sectors, which is within the max LBA 35156656127 of drive. And this IO is completed successfully from the slice of parsed block trace though reporting the warning message.
>>> 8,64 7 13 0.039401337 19176 Q RA 35156656120 + 8 [systemd-udevd]
>>> 8,64 7 15 0.039403946 19176 P N [systemd-udevd]
>>> 8,64 7 16 0.039405132 19176 I RA 35156656120 + 8 [systemd-udevd]
>>> 8,64 7 18 0.039411554 19176 D RA 35156656120 + 8 [systemd-udevd]
>>> 8,64 0 40 0.039479055 0 C RA 35156656120 + 8 [0]
>>>
>>> It may need to know where calculate "bio_end_sector" value as 35156656128. I have patched libata and sd driver for Dual Actuator.
>>>
>>>
>>>
>>> From: Paolo Valente <mailto:paolo.valente@linaro.org>
>>> Sent: Wednesday, August 10, 2022 6:22 PM
>>> To: Rory Chen <mailto:rory.c.chen@seagate.com>
>>> Cc: Arie van der Hoeven <mailto:arie.vanderhoeven@seagate.com>; Muhammad
>>> Ahmad <mailto:muhammad.ahmad@seagate.com>; mailto:linux-block@vger.kernel.org
>>> <mailto:linux-block@vger.kernel.org>; mailto:linux-kernel@vger.kernel.org
>>> <mailto:linux-kernel@vger.kernel.org>; Jan Kara <mailto:jack@suse.cz>;
>>> mailto:andrea.righi@canonical.com <mailto:andrea.righi@canonical.com>;
>>> mailto:glen.valante@linaro.org <mailto:glen.valante@linaro.org>; mailto:axboe@kernel.dk
>>> <mailto:axboe@kernel.dk>; Tyler Erickson <mailto:tyler.erickson@seagate.com>;
>>> Michael English <mailto:michael.english@seagate.com>; Andrew Ring
>>> <mailto:andrew.ring@seagate.com>; Varun Boddu <mailto:varunreddy.boddu@seagate.com>
>>> Subject: Re: [PATCH 0/8] block, bfq: extend bfq to support
>>> multi-actuator drives
>>>
>>>
>>> This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email.
>>>
>>>
>>>> Il giorno 9 ago 2022, alle ore 05:47, Rory Chen <mailto:rory.c.chen@seagate.com> ha scritto:
>>>>
>>>> Resend the mail as plain text because previous mail with rich text
>>>> makes some mess and forget to add others at Seagate who worked on
>>>> validating the patch as well(Muhammad, Michael, Andrew, Varun,Tyler)
>>>>
>>>> Hi Paolo,
>>>>
>>>
>>> Hi
>>>
>>>> I am from Seagate China and face a problem when I'm evaluating the bfq patches. Could you please check?
>>>> Thanks
>>>>
>>>> Issue statement
>>>> When running performance test on bfq patch, I observed warning message "bfq_actuator_index: bio sector out of ranges: end=35156656128" and OS hung suddenly after some hours.
>>>> The warning message is reported from function bfq_actuator_index which determines IO request is in which index of actuators. The bio_end_sector is 35156656128 but the max LBA for the drive is 35156656127 so it's beyond the LBA range.
>>>
>>> Yep, this sanity check fails if the end sector of a new IO does not belong to any sector range.
>>>
>>>> I captured the block trace and didn't found request LBA 35156656128 instead only found max request LBA 35156656127.
>>>
>>> Maybe in the trace you see only start sectors? The failed check si performed on end sectors instead.
>>>
>>> At any rate, there seems to be an off-by-one error in the value(s) stored in the sector field(s) of the blk_independent_access_range data structure.
>>>
>>> I guess we may need some help/feedback from people competent on this stuff.
>>>
>>>> I'm not sure if this warning message is related to later OS hung.
>>>>
>>>
>>> Not easy to say. At any rate, we can try with a development version of bfq. It can help us detect the possible cause of this hang. But let's see where we get with this sector error first.
>>>
>>> Thank you for testing this extended version of bfq, Paolo
>>>
>>>>
>>>> Problem environment
>>>> Kernel base is 5.18.9
>>>> Test HDD drive is Seagate ST18000NM0092 dual actuator SATA.
>>>> Actuator LBA mapping by reading VPD B9 Concurrent positioning ranges
>>>> VPD page:
>>>> LBA range number:0
>>>> number of storage elements:1
>>>> starting LBA:0x0
>>>> number of LBAs:0x417c00000 [17578328064] LBA range number:1 number
>>>> of storage elements:1 starting LBA:0x417c00000 number of
>>>> LBAs:0x417c00000 [17578328064]
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> From: Paolo Valente <mailto:paolo.valente@linaro.org>
>>>> Sent: Thursday, June 23, 2022 8:53 AM
>>>> To: Jens Axboe <mailto:axboe@kernel.dk>
>>>> Cc: mailto:linux-block@vger.kernel.org <mailto:linux-block@vger.kernel.org>;
>>>> mailto:linux-kernel@vger.kernel.org <mailto:linux-kernel@vger.kernel.org>;
>>>> mailto:jack@suse.cz <mailto:jack@suse.cz>; mailto:andrea.righi@canonical.com
>>>> <mailto:andrea.righi@canonical.com>; mailto:glen.valante@linaro.org
>>>> <mailto:glen.valante@linaro.org>; Arie van der Hoeven
>>>> <mailto:arie.vanderhoeven@seagate.com>; Paolo Valente
>>>> <mailto:paolo.valente@linaro.org>
>>>> Subject: [PATCH 0/8] block, bfq: extend bfq to support
>>>> multi-actuator drives
>>>>
>>>>
>>>> This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email.
>>>>
>>>>
>>>> Hi,
>>>> this patch series extends BFQ so as to optimize I/O dispatch to
>>>> multi-actuator drives. In particular, this extension addresses the
>>>> following issue. Multi-actuator drives appear as a single device to
>>>> the I/O subsystem [1]. Yet they address commands to different
>>>> actuators internally, as a function of Logical Block Addressing
>>>> (LBAs). A given sector is reachable by only one of the actuators.
>>>> For example, Seagate's Serial Advanced Technology Attachment (SATA)
>>>> version contains two actuators and maps the lower half of the SATA
>>>> LBA space to the lower actuator and the upper half to the upper actuator.
>>>>
>>>> Evidently, to fully utilize actuators, no actuator must be left idle
>>>> or underutilized while there is pending I/O for it. To reach this
>>>> goal, the block layer must somehow control the load of each actuator
>>>> individually. This series enriches BFQ with such a per-actuator
>>>> control, as a first step. Then it also adds a simple mechanism for
>>>> guaranteeing that actuators with pending I/O are never left idle.
>>>>
>>>> See [1] for a more detailed overview of the problem and of the
>>>> solutions implemented in this patch series. There you will also find
>>>> some preliminary performance results.
>>>>
>>>> Thanks,
>>>> Paolo
>>>>
>>>> [1]
>>>> https://secure-web.cisco.com/1hcxnN1C3h1nW7mby7S66_LE8szirQwbQI0fBpY
>>>> eP
>>>> rA0GTWfyuQyl0GpZaOn32xMSkNT0BUQWloDHFzZ23aYDZdi8NfdrEFLY9pQDBblIvn08
>>>> LR
>>>> iTVoIOUC8zWSG_r2PCyLtx3ppZq5cWOib_8azxteRRcbKWGdbLPSqg9hfSJSqltth0By
>>>> LO
>>>> NHEoI3p3e9QNIn6nVAeQbsT3aOQe-F95XrQvaPrFJXx6RGL9kDXyfkbXIHcdcLBf895g
>>>> YB
>>>> Fn5S2WjBDQq2kzDzZOlc1HekRUhg0qDQcFY6NydVfrqNfLbpAHAth6KyREscQhVTMVRE
>>>> EV
>>>> a1b6bQByX6grF5pn3pTIo0lODyfX6yRmcbReSYNfOZ65ZPvp-nH530FQ-5nXoRxFf74W
>>>> IK
>>>> DrNTALs3xQvg03DH4jLez-T2M9xEu-sfEDAEdTGF7BcnmBW6vrPO4_p3k4/https%3A%
>>>> 2F
>>>> %2Fwww.linaro.org%2Fblog%2Fbudget-fair-queueing-bfq-linux-io-schedul
>>>> er -optimizations-for-multi-actuator-sata-hard-drives%2F
>>>>
>>>> Davide Zini (3):
>>>> block, bfq: split also async bfq_queues on a per-actuator basis
>>>> block, bfq: inject I/O to underutilized actuators block, bfq:
>>>> balance I/O injection among underutilized actuators
>>>>
>>>> Federico Gavioli (1):
>>>> block, bfq: retrieve independent access ranges from request queue
>>>>
>>>> Paolo Valente (4):
>>>> block, bfq: split sync bfq_queues on a per-actuator basis block,
>>>> bfq: forbid stable merging of queues associated with different
>>>> actuators block, bfq: turn scalar fields into arrays in bfq_io_cq
>>>> block, bfq:
>>>> turn BFQ_NUM_ACTUATORS into BFQ_MAX_ACTUATORS
>>>>
>>>> block/bfq-cgroup.c | 97 +++++----
>>>> block/bfq-iosched.c | 488
>>>> +++++++++++++++++++++++++++++---------------
>>>> block/bfq-iosched.h | 149 ++++++++++----
>>>> block/bfq-wf2q.c | 2 +-
>>>> 4 files changed, 493 insertions(+), 243 deletions(-)
>>>>
>>>> --
>>>> 2.20.1
>>>>
>>>>
>>>> Seagate Internal
>>>>
>>>> Seagate Internal
>>>
>>> Seagate Internal
>>
>> Seagate Internal
>
>
> Seagate Internal
>
> Seagate Internal

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