RE: LTO-4 iSCSI performance less than expected ...

2017-04-03 Thread David C. Partridge
Hmmm I couldn’t find anything about this in the stinit docs.

 

Dave

 

From: open-iscsi@googlegroups.com [mailto:open-iscsi@googlegroups.com] On 
Behalf Of The Lee-Man
Sent: 03 April 2017 20:05
To: open-iscsi
Subject: Re: LTO-4 iSCSI performance less than expected ...

 

On Friday, March 31, 2017 at 2:23:30 PM UTC-7, david.partri...@perdrix.co.uk 
wrote:

I don't know?  How do I find out?  Should I have it set?

 

Have you set the Write Immediate Filemark option for the st driver? 



There are a couple of ways to enable writing immediate filemarks in the st 
driver. One is to use the MTWEOFI ioctl(). If you have access to the source 
code for your application, this is a good way to go.

But I added a user-settable option with kernel commit  
c743e44fbb1f8668941e83de07662b1ecd33d083. It allows you to tell the st driver 
to write immediate file marks by setting a sysfs attribute.

-- 



-- 
You received this message because you are subscribed to the Google Groups 
"open-iscsi" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to open-iscsi+unsubscr...@googlegroups.com.
To post to this group, send email to open-iscsi@googlegroups.com.
Visit this group at https://groups.google.com/group/open-iscsi.
For more options, visit https://groups.google.com/d/optout.


Re: [PATCH] libiscsi: use vzalloc for large allocations in iscsi_pool_init

2017-04-03 Thread Chet L
On Mon, Apr 3, 2017 at 6:30 AM, Kyle Fortin  wrote:

>
> for (i = 0; i < q->max; i++)
> kfree(q->pool[i]);
> -   kfree(q->pool);
> +   if (q->is_pool_vmalloc)

you could do something like:

if (is_vmalloc_addr(q->pool))
vfree(...);
else
kfree(..);

And then remove the bool.


Chetan

-- 
You received this message because you are subscribed to the Google Groups 
"open-iscsi" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to open-iscsi+unsubscr...@googlegroups.com.
To post to this group, send email to open-iscsi@googlegroups.com.
Visit this group at https://groups.google.com/group/open-iscsi.
For more options, visit https://groups.google.com/d/optout.


Re: [PATCH] libiscsi: use vzalloc for large allocations in iscsi_pool_init

2017-04-03 Thread Johannes Thumshirn
On Mon, Apr 03, 2017 at 06:30:21AM -0700, Kyle Fortin wrote:
> iscsiadm session login can fail with the following error:
> 
> iscsiadm: Could not login to [iface: default, target: iqn.1986-03.com...
> iscsiadm: initiator reported error (9 - internal error)
> 
> When /etc/iscsi/iscsid.conf sets node.session.cmds_max = 4096, it results
> in 64K-sized kmallocs per session.  A system under fragmented slab
> pressure may not have any 64K objects available and fail iscsiadm session
> login. Even though memory objects of a smaller size are available, the
> large order allocation ends up failing.
> 
> The kernel will print a warning and dump_stack, like below:

There is a series of patches in Andrew's mmotm tree, which introduces
a kvmalloc() function, that does exactly what you're looking for.

Maybe you want to base your patch on top of it.

-- 
Johannes Thumshirn  Storage
jthumsh...@suse.de+49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

-- 
You received this message because you are subscribed to the Google Groups 
"open-iscsi" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to open-iscsi+unsubscr...@googlegroups.com.
To post to this group, send email to open-iscsi@googlegroups.com.
Visit this group at https://groups.google.com/group/open-iscsi.
For more options, visit https://groups.google.com/d/optout.


Re: [PATCH] libiscsi: use vzalloc for large allocations in iscsi_pool_init

2017-04-03 Thread Kyle Fortin
On Apr 3, 2017, at 9:41 AM, Johannes Thumshirn  wrote:
> 
> On Mon, Apr 03, 2017 at 06:30:21AM -0700, Kyle Fortin wrote:
>> iscsiadm session login can fail with the following error:
>> 
>> iscsiadm: Could not login to [iface: default, target: iqn.1986-03.com...
>> iscsiadm: initiator reported error (9 - internal error)
>> 
>> When /etc/iscsi/iscsid.conf sets node.session.cmds_max = 4096, it results
>> in 64K-sized kmallocs per session.  A system under fragmented slab
>> pressure may not have any 64K objects available and fail iscsiadm session
>> login. Even though memory objects of a smaller size are available, the
>> large order allocation ends up failing.
>> 
>> The kernel will print a warning and dump_stack, like below:
> 
> There is a series of patches in Andrew's mmotm tree, which introduces
> a kvmalloc() function, that does exactly what you're looking for.
> 
> Maybe you want to base your patch on top of it.
> 
> -- 
> Johannes Thumshirn  Storage
> jthumsh...@suse.de+49 911 74053 689
> SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
> GF: Felix Imendörffer, Jane Smithard, Graham Norton
> HRB 21284 (AG Nürnberg)
> Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

Thanks Johannes.  I’ll take a look.
--
Kyle Fortin - Oracle Linux Engineering




-- 
You received this message because you are subscribed to the Google Groups 
"open-iscsi" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to open-iscsi+unsubscr...@googlegroups.com.
To post to this group, send email to open-iscsi@googlegroups.com.
Visit this group at https://groups.google.com/group/open-iscsi.
For more options, visit https://groups.google.com/d/optout.


Re: LTO-4 iSCSI performance less than expected ...

2017-04-03 Thread The Lee-Man
On Friday, March 31, 2017 at 2:23:30 PM UTC-7, 
david.partri...@perdrix.co.uk wrote:
>
> I don't know?  How do I find out?  Should I have it set?
>
>>
>> Have you set the Write Immediate Filemark option for the st driver? 
>>
>

There are a couple of ways to enable writing immediate filemarks in the st 
driver. One is to use the MTWEOFI ioctl(). If you have access to the source 
code for your application, this is a good way to go.

But I added a user-settable option with kernel commit  
c743e44fbb1f8668941e83de07662b1ecd33d083. It allows you to tell the st 
driver to write immediate file marks by setting a sysfs attribute.

-- 
You received this message because you are subscribed to the Google Groups 
"open-iscsi" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to open-iscsi+unsubscr...@googlegroups.com.
To post to this group, send email to open-iscsi@googlegroups.com.
Visit this group at https://groups.google.com/group/open-iscsi.
For more options, visit https://groups.google.com/d/optout.