Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-11 Thread Martin K. Petersen 
> "Ewan" == Ewan D Milne  writes:

Ewan> In the upstream kernel queue_max_sectors_store() does not permit
Ewan> you to set a value larger than the device-imposed limit.  This
Ewan> value, stored in q->limits.max_dev_sectors, is not visible via the
Ewan> block queue sysfs interface.

I should refresh the patch that exposes that. There were a few comments
and I never got around to rolling those in.

-- 
Martin K. Petersen  Oracle Linux Engineering
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-11 Thread Laurence Oberman 
As a follow up to this issue.

I looked at modifying the LIO target code to allow a larger max_sectors_kb 
exported to the initiator for the nvme devices but had some issues.
In the end I created 15 fileio devices using 200GB of ramdisk and exported 
those so I could test 4MB I/O from the initiator.

These allow the 4MB setting on the upstream kernel.

[root@srptest ~]# sg_inq -p 0xb0 /dev/sdk
VPD INQUIRY: Block limits page (SBC)
  Maximum compare and write length: 1 blocks
  Optimal transfer length granularity: 1 blocks
  Maximum transfer length: 16384 blocks
  Optimal transfer length: 16384 blocks
  Maximum prefetch, xdread, xdwrite transfer length: 0 blocks

The sg_map issues I am having on the RHEL kernel are likely due to the "proper" 
max sector size being ignored.
I am testing latest upstream now 4.5.0 with all the sg related patches to see 
if that's stable.

Thanks

Laurence Oberman
Principal Software Maintenance Engineer
Red Hat Global Support Services

- Original Message -
From: "Laurence Oberman" <lober...@redhat.com>
To: emi...@redhat.com
Cc: "Martin K. Petersen" <martin.peter...@oracle.com>, "linux-scsi" 
<linux-scsi@vger.kernel.org>, linux-r...@vger.kernel.org
Sent: Friday, April 8, 2016 9:11:19 AM
Subject: Re: Cant write to max_sectors_kb on 4.5.0  SRP target

Hi Ewan, 

OK, that makes sense.
I suspected after everybody's responses that RHEL was somehow ignoring the 
array imposed limit here.
I actually got lucky because I needed to be able to issue 4MB IO'S to reproduce 
the failures seen
at the customer on the initiator side.

Looking at the target-LIO array now its clamped to 1MB I/O sizes which makes 
sense.
I really was not focusing on the array at the time expecting it may chop the 
I/O up as many do.

Knowing what's up now I can continue to test and figure out what patches I need 
to pull in to SRP on RHEL to make progress.

Thank you to all that responded.

Laurence Oberman
Principal Software Maintenance Engineer
Red Hat Global Support Services

- Original Message -
From: "Ewan D. Milne" <emi...@redhat.com>
To: "Laurence Oberman" <lober...@redhat.com>
Cc: "Martin K. Petersen" <martin.peter...@oracle.com>, "linux-scsi" 
<linux-scsi@vger.kernel.org>, linux-r...@vger.kernel.org
Sent: Friday, April 8, 2016 8:39:52 AM
Subject: Re: Cant write to max_sectors_kb on 4.5.0  SRP target

The version of RHEL you are using does not have:

commit ca369d51b3e1649be4a72addd6d6a168cfb3f537
Author: Martin K. Petersen <martin.peter...@oracle.com>
Date:   Fri Nov 13 16:46:48 2015 -0500

block/sd: Fix device-imposed transfer length limits

(which will be added during the next update).

In the upstream kernel queue_max_sectors_store() does not
permit you to set a value larger than the device-imposed
limit.  This value, stored in q->limits.max_dev_sectors,
is not visible via the block queue sysfs interface.

The code that sets q->limits.max_sectors and q->limits.io_opt
in sd.c does not take the device limit into account, but
the sysfs code to change max_sectors ("max_sectors_kb") does.

So there are a couple of problems here, one is that RHEL
is not clamping to the device limit, and the other one is
that neither RHEL nor upstream kernels take the device limit
into account when setting q->limits.io_opt.  This only seems
to be a problem for you because your target is reporting
an optimal I/O size in VPD page B0 that is *smaller* than
the reported maximum I/O size.

The target is clearly reporting inconsistent data, the
question is whether we should change the code to clamp the
optimal I/O size, or whether we should assume the value
the target is reporting is wrong.

So the question is:  does the target actually process
requests that are larger than the VPD page B0 reported
maximum size?  If so, maybe we should just issue a warning
message rather than reducing the optimal I/O size.

-Ewan


On Fri, 2016-04-08 at 04:31 -0400, Laurence Oberman wrote:
> Hello Martin
> 
> Yes, Ewan also noticed that.
> 
> This started out as me testing the SRP stack on RHEL 7.2 and baselining 
> against upstream.
> We have a customer that requires 4MB I/O.
> I bumped into a number of SRP issues including sg_map failures so started 
> reviewing upstream changes to the SRP code and patches.
> 
> The RHEL kernel is ignoring this so perhaps we have an issue on our side 
> (RHEL kernel) and upstream is behaving as it should.
> 
> What is intersting is that I cannot change the max_sectors_kb at all on the 
> upstream for the SRP LUNS.
> 
> Here is an HP SmartArray LUN
> 
> [root@srptest ~]#  sg_inq --p 0xb0 /dev/sda
> VPD INQUIRY: page=0xb0
> inquiry: field in cdb illegal (page not supported)    Known that its 
> not supported
> 
> However
> 
> /sys/block/sda/queue
> 
> [root@s

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-08 Thread Laurence Oberman 
Hi Ewan, 

OK, that makes sense.
I suspected after everybody's responses that RHEL was somehow ignoring the 
array imposed limit here.
I actually got lucky because I needed to be able to issue 4MB IO'S to reproduce 
the failures seen
at the customer on the initiator side.

Looking at the target-LIO array now its clamped to 1MB I/O sizes which makes 
sense.
I really was not focusing on the array at the time expecting it may chop the 
I/O up as many do.

Knowing what's up now I can continue to test and figure out what patches I need 
to pull in to SRP on RHEL to make progress.

Thank you to all that responded.

Laurence Oberman
Principal Software Maintenance Engineer
Red Hat Global Support Services

- Original Message -
From: "Ewan D. Milne" <emi...@redhat.com>
To: "Laurence Oberman" <lober...@redhat.com>
Cc: "Martin K. Petersen" <martin.peter...@oracle.com>, "linux-scsi" 
<linux-scsi@vger.kernel.org>, linux-r...@vger.kernel.org
Sent: Friday, April 8, 2016 8:39:52 AM
Subject: Re: Cant write to max_sectors_kb on 4.5.0  SRP target

The version of RHEL you are using does not have:

commit ca369d51b3e1649be4a72addd6d6a168cfb3f537
Author: Martin K. Petersen <martin.peter...@oracle.com>
Date:   Fri Nov 13 16:46:48 2015 -0500

block/sd: Fix device-imposed transfer length limits

(which will be added during the next update).

In the upstream kernel queue_max_sectors_store() does not
permit you to set a value larger than the device-imposed
limit.  This value, stored in q->limits.max_dev_sectors,
is not visible via the block queue sysfs interface.

The code that sets q->limits.max_sectors and q->limits.io_opt
in sd.c does not take the device limit into account, but
the sysfs code to change max_sectors ("max_sectors_kb") does.

So there are a couple of problems here, one is that RHEL
is not clamping to the device limit, and the other one is
that neither RHEL nor upstream kernels take the device limit
into account when setting q->limits.io_opt.  This only seems
to be a problem for you because your target is reporting
an optimal I/O size in VPD page B0 that is *smaller* than
the reported maximum I/O size.

The target is clearly reporting inconsistent data, the
question is whether we should change the code to clamp the
optimal I/O size, or whether we should assume the value
the target is reporting is wrong.

So the question is:  does the target actually process
requests that are larger than the VPD page B0 reported
maximum size?  If so, maybe we should just issue a warning
message rather than reducing the optimal I/O size.

-Ewan


On Fri, 2016-04-08 at 04:31 -0400, Laurence Oberman wrote:
> Hello Martin
> 
> Yes, Ewan also noticed that.
> 
> This started out as me testing the SRP stack on RHEL 7.2 and baselining 
> against upstream.
> We have a customer that requires 4MB I/O.
> I bumped into a number of SRP issues including sg_map failures so started 
> reviewing upstream changes to the SRP code and patches.
> 
> The RHEL kernel is ignoring this so perhaps we have an issue on our side 
> (RHEL kernel) and upstream is behaving as it should.
> 
> What is intersting is that I cannot change the max_sectors_kb at all on the 
> upstream for the SRP LUNS.
> 
> Here is an HP SmartArray LUN
> 
> [root@srptest ~]#  sg_inq --p 0xb0 /dev/sda
> VPD INQUIRY: page=0xb0
> inquiry: field in cdb illegal (page not supported)    Known that its 
> not supported
> 
> However
> 
> /sys/block/sda/queue
> 
> [root@srptest queue]# cat max_hw_sectors_kb max_sectors_kb
> 4096
> 1280
> [root@srptest queue]# echo 4096 > max_sectors_kb
> [root@srptest queue]# cat max_hw_sectors_kb max_sectors_kb
> 4096
> 4096
> 
> On the SRP LUNS I am unable to change to a lower value than  max_sectors_kb 
> unless I change it to 128
> So perhaps the size on the array is the issue here as Nicholas said and the 
> RHEL kernel has a bug and ignores it.
> 
> /sys/block/sdc/queue
> 
> [root@srptest queue]# cat max_hw_sectors_kb max_sectors_kb
> 4096
> 1280
> 
> [root@srptest queue]# echo 512 > max_sectors_kb
> -bash: echo: write error: Invalid argument
> 
> [root@srptest queue]# echo 256 > max_sectors_kb
> -bash: echo: write error: Invalid argument
> 
> 128 works
> [root@srptest queue]# echo 128 > max_sectors_kb
> 
> 
> 
> 
> Laurence Oberman
> Principal Software Maintenance Engineer
> Red Hat Global Support Services
> 
> - Original Message -----
> From: "Martin K. Petersen" <martin.peter...@oracle.com>
> To: "Laurence Oberman" <lober...@redhat.com>
> Cc: "linux-scsi" <linux-scsi@vger.kernel.org>, linux-r...@vger.kernel.org
> Sent: Thursday, April 7, 2016 11:00:16 PM
> Subject: Re: Cant writ

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-08 Thread Ewan D. Milne 
The version of RHEL you are using does not have:

commit ca369d51b3e1649be4a72addd6d6a168cfb3f537
Author: Martin K. Petersen <martin.peter...@oracle.com>
Date:   Fri Nov 13 16:46:48 2015 -0500

block/sd: Fix device-imposed transfer length limits

(which will be added during the next update).

In the upstream kernel queue_max_sectors_store() does not
permit you to set a value larger than the device-imposed
limit.  This value, stored in q->limits.max_dev_sectors,
is not visible via the block queue sysfs interface.

The code that sets q->limits.max_sectors and q->limits.io_opt
in sd.c does not take the device limit into account, but
the sysfs code to change max_sectors ("max_sectors_kb") does.

So there are a couple of problems here, one is that RHEL
is not clamping to the device limit, and the other one is
that neither RHEL nor upstream kernels take the device limit
into account when setting q->limits.io_opt.  This only seems
to be a problem for you because your target is reporting
an optimal I/O size in VPD page B0 that is *smaller* than
the reported maximum I/O size.

The target is clearly reporting inconsistent data, the
question is whether we should change the code to clamp the
optimal I/O size, or whether we should assume the value
the target is reporting is wrong.

So the question is:  does the target actually process
requests that are larger than the VPD page B0 reported
maximum size?  If so, maybe we should just issue a warning
message rather than reducing the optimal I/O size.

-Ewan


On Fri, 2016-04-08 at 04:31 -0400, Laurence Oberman wrote:
> Hello Martin
> 
> Yes, Ewan also noticed that.
> 
> This started out as me testing the SRP stack on RHEL 7.2 and baselining 
> against upstream.
> We have a customer that requires 4MB I/O.
> I bumped into a number of SRP issues including sg_map failures so started 
> reviewing upstream changes to the SRP code and patches.
> 
> The RHEL kernel is ignoring this so perhaps we have an issue on our side 
> (RHEL kernel) and upstream is behaving as it should.
> 
> What is intersting is that I cannot change the max_sectors_kb at all on the 
> upstream for the SRP LUNS.
> 
> Here is an HP SmartArray LUN
> 
> [root@srptest ~]#  sg_inq --p 0xb0 /dev/sda
> VPD INQUIRY: page=0xb0
> inquiry: field in cdb illegal (page not supported)    Known that its 
> not supported
> 
> However
> 
> /sys/block/sda/queue
> 
> [root@srptest queue]# cat max_hw_sectors_kb max_sectors_kb
> 4096
> 1280
> [root@srptest queue]# echo 4096 > max_sectors_kb
> [root@srptest queue]# cat max_hw_sectors_kb max_sectors_kb
> 4096
> 4096
> 
> On the SRP LUNS I am unable to change to a lower value than  max_sectors_kb 
> unless I change it to 128
> So perhaps the size on the array is the issue here as Nicholas said and the 
> RHEL kernel has a bug and ignores it.
> 
> /sys/block/sdc/queue
> 
> [root@srptest queue]# cat max_hw_sectors_kb max_sectors_kb
> 4096
> 1280
> 
> [root@srptest queue]# echo 512 > max_sectors_kb
> -bash: echo: write error: Invalid argument
> 
> [root@srptest queue]# echo 256 > max_sectors_kb
> -bash: echo: write error: Invalid argument
> 
> 128 works
> [root@srptest queue]# echo 128 > max_sectors_kb
> 
> 
> 
> 
> Laurence Oberman
> Principal Software Maintenance Engineer
> Red Hat Global Support Services
> 
> - Original Message -
> From: "Martin K. Petersen" <martin.peter...@oracle.com>
> To: "Laurence Oberman" <lober...@redhat.com>
> Cc: "linux-scsi" <linux-scsi@vger.kernel.org>, linux-r...@vger.kernel.org
> Sent: Thursday, April 7, 2016 11:00:16 PM
> Subject: Re: Cant write to max_sectors_kb on 4.5.0  SRP target
> 
> >>>>> "Laurence" == Laurence Oberman <lober...@redhat.com> writes:
> 
> Laurence,
> 
> The target is reporting inconsistent values here:
> 
> > [root@srptest queue]# sg_inq --p 0xb0 /dev/sdb
> > VPD INQUIRY: Block limits page (SBC)
> >   Maximum compare and write length: 1 blocks
> >   Optimal transfer length granularity: 256 blocks
> >   Maximum transfer length: 256 blocks
> >   Optimal transfer length: 768 blocks
> 
> OPTIMAL TRANSFER LENGTH GRANULARITY roughly translates to physical block
> size or RAID chunk size. It's the smallest I/O unit that does not
> require read-modify-write. It would typically be either 1 or 8 blocks
> for a drive and maybe 64, 128 or 256 for a RAID5 array. io_min in
> queue_limits.
> 
> OPTIMAL TRANSFER LENGTH indicates the stripe width and is a multiple of
> OPTIMAL TRANSFER LENGTH GRANULARITY. io_opt in queue_limits.
> 
> MAXIMUM TRANSFER LENGTH indicates the biggest READ/WRITE command the
> dev

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-08 Thread Laurence Oberman 
o- mapped_lun28 
 [lun28 
block/block-29 (rw)]
  | | | | o- mapped_lun29 
 [lun29 
block/block-30 (rw)]
  | | | o- ib.4f6e72000390fe7c7cfe900300726ed3 
. [Mapped LUNs: 30]
  | | |   o- mapped_lun0 
... [lun0 
block/block-1 (rw)]
  | | |   o- mapped_lun1 
... [lun1 
block/block-2 (rw)]
  | | |   o- mapped_lun2 
... [lun2 
block/block-3 (rw)]
  | | |   o- mapped_lun3 
... [lun3 
block/block-4 (rw)]
  | | |   o- mapped_lun4 
... [lun4 
block/block-5 (rw)]
..
,,

Laurence Oberman
Principal Software Maintenance Engineer
Red Hat Global Support Services

- Original Message -
From: "Nicholas A. Bellinger" <n...@linux-iscsi.org>
To: "Laurence Oberman" <lober...@redhat.com>
Cc: "linux-scsi" <linux-scsi@vger.kernel.org>, linux-r...@vger.kernel.org, 
"target-devel" <target-de...@vger.kernel.org>
Sent: Friday, April 8, 2016 1:30:28 AM
Subject: Re: Cant write to max_sectors_kb on 4.5.0  SRP target

Hi Laurence,

On Thu, 2016-04-07 at 17:15 -0400, Laurence Oberman wrote:
> Hello
> 
> I have been testing the SRP initiator code to an LIO array here and
> part of the testing requires me to set the max_sectors_kb size to get
> 4k I/O's.
> This has been due to me having to debug various sg_map issues.
> 
> Linux srptest 4.5.0 #2 SMP Thu Apr 7 16:14:38 EDT 2016 x86_64 x86_64
> x86_64 GNU/Linux
> This kernel has the scan patch from Hannes, as well as the "[PATCH]
> IB/mlx5: Expose correct max_sge_rd limit" patch. 
> However, I also tested with vanilla 4.5.0 as well and its the same
> issue.
> 
> For some reason I cannot change the max_sectors_kb size on 4.5.0 here.
> 
> I chatted with Ewan about it as well and he reminded me about Martins
> changes so wondering if that's playing into this.
> 
> Take /dev/sdb as an example
> 
> [root@srptest queue]# sg_inq --p 0xb0 /dev/sdb
> VPD INQUIRY: Block limits page (SBC)
>   Maximum compare and write length: 1 blocks
>   Optimal transfer length granularity: 256 blocks
>   Maximum transfer length: 256 blocks
>   Optimal transfer length: 768 blocks
>   Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
> 

Just curious what target backend this is with..?

Specifically the optimal transfer length granularity and optimal
transfer length may be reported by underlying backend device (eg:
IBLOCK) in spc_emulate_evpd_b0(). 

What does 'head /sys/kernel/config/target/core/$HBA/$DEV/attrib/*'
of the backend device in question look like..?

--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-08 Thread Laurence Oberman 
vcTim Util
03:56:57 sdc  0  000  1092608  0 1067 10241024  
   3 2  0   74
03:56:57 dm-4 0  000  1092608  0 1067 10241024  
   3 2  0   79
03:56:58 sdc  0  000  1070080  0 1045 10241024  
   3 2  0   73
03:56:58 dm-4 0  000  1070080  0 1045 10241024  
   3 2  0   78
03:56:59 sdc  0  000  1101824  0 1076 10241024  
   3 2  0   72
03:56:59 dm-4 0  000  1101824  0 1076 10241024  
   3 2  0   77


Laurence Oberman
Principal Software Maintenance Engineer
Red Hat Global Support Services


Laurence Oberman
Principal Software Maintenance Engineer
Red Hat Global Support Services

- Original Message -
From: "Bart Van Assche" <bart.vanass...@sandisk.com>
To: "Laurence Oberman" <lober...@redhat.com>, "linux-scsi" 
<linux-scsi@vger.kernel.org>, linux-r...@vger.kernel.org
Sent: Thursday, April 7, 2016 10:49:58 PM
Subject: Re: Cant write to max_sectors_kb on 4.5.0 SRP target

On 04/07/16 14:16, Laurence Oberman wrote:
> I have been testing the SRP initiator code to an LIO array here and
 > part of the testing requires me to set the max_sectors_kb size to
 > get 4k I/O's.
.
Hello Laurence,

Have you already tried to set the max_sect parameter in 
/etc/srp_daemon.conf (assuming you are using srptools >= 1.0.3 for SRP 
login) ? Additionally, writing something like "options ib_srp 
cmd_sg_entries=255" into /etc/modprobe.d/ib_srp.conf will increase the 
maximum SRP transfer size.

Bart.
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-07 Thread Nicholas A. Bellinger 
Hi Laurence,

On Thu, 2016-04-07 at 17:15 -0400, Laurence Oberman wrote:
> Hello
> 
> I have been testing the SRP initiator code to an LIO array here and
> part of the testing requires me to set the max_sectors_kb size to get
> 4k I/O's.
> This has been due to me having to debug various sg_map issues.
> 
> Linux srptest 4.5.0 #2 SMP Thu Apr 7 16:14:38 EDT 2016 x86_64 x86_64
> x86_64 GNU/Linux
> This kernel has the scan patch from Hannes, as well as the "[PATCH]
> IB/mlx5: Expose correct max_sge_rd limit" patch. 
> However, I also tested with vanilla 4.5.0 as well and its the same
> issue.
> 
> For some reason I cannot change the max_sectors_kb size on 4.5.0 here.
> 
> I chatted with Ewan about it as well and he reminded me about Martins
> changes so wondering if that's playing into this.
> 
> Take /dev/sdb as an example
> 
> [root@srptest queue]# sg_inq --p 0xb0 /dev/sdb
> VPD INQUIRY: Block limits page (SBC)
>   Maximum compare and write length: 1 blocks
>   Optimal transfer length granularity: 256 blocks
>   Maximum transfer length: 256 blocks
>   Optimal transfer length: 768 blocks
>   Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
> 

Just curious what target backend this is with..?

Specifically the optimal transfer length granularity and optimal
transfer length may be reported by underlying backend device (eg:
IBLOCK) in spc_emulate_evpd_b0(). 

What does 'head /sys/kernel/config/target/core/$HBA/$DEV/attrib/*'
of the backend device in question look like..?

--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-07 Thread Martin K. Petersen 
> "Laurence" == Laurence Oberman  writes:

Laurence,

The target is reporting inconsistent values here:

> [root@srptest queue]# sg_inq --p 0xb0 /dev/sdb
> VPD INQUIRY: Block limits page (SBC)
>   Maximum compare and write length: 1 blocks
>   Optimal transfer length granularity: 256 blocks
>   Maximum transfer length: 256 blocks
>   Optimal transfer length: 768 blocks

OPTIMAL TRANSFER LENGTH GRANULARITY roughly translates to physical block
size or RAID chunk size. It's the smallest I/O unit that does not
require read-modify-write. It would typically be either 1 or 8 blocks
for a drive and maybe 64, 128 or 256 for a RAID5 array. io_min in
queue_limits.

OPTIMAL TRANSFER LENGTH indicates the stripe width and is a multiple of
OPTIMAL TRANSFER LENGTH GRANULARITY. io_opt in queue_limits.

MAXIMUM TRANSFER LENGTH indicates the biggest READ/WRITE command the
device can handle in a single command. In this case 256 blocks so that's
128K. max_dev_sectors in queue_limits.

>From SBC:

"A MAXIMUM TRANSFER LENGTH field set to a non-zero value indicates the
maximum transfer length in logical blocks that the device server accepts
for a single command shown in table 250. If a device server receives one
of these commands with a transfer size greater than this value, then the
device server shall terminate the command with CHECK CONDITION status
[...]"

So those reported values are off.

   logical block size <= physical block size <= OTLG <= OTL <= MTL

Or in terms of queue_limits:

   lbs <= pbs <= io_min <= io_opt <=
   min_not_zero(max_dev_sectors, max_hw_sectors, max_sectors)

-- 
Martin K. Petersen  Oracle Linux Engineering
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Cant write to max_sectors_kb on 4.5.0 SRP target

2016-04-07 Thread Bart Van Assche 

On 04/07/16 14:16, Laurence Oberman wrote:

I have been testing the SRP initiator code to an LIO array here and

> part of the testing requires me to set the max_sectors_kb size to
> get 4k I/O's.
   .
Hello Laurence,

Have you already tried to set the max_sect parameter in 
/etc/srp_daemon.conf (assuming you are using srptools >= 1.0.3 for SRP 
login) ? Additionally, writing something like "options ib_srp 
cmd_sg_entries=255" into /etc/modprobe.d/ib_srp.conf will increase the 
maximum SRP transfer size.


Bart.
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html