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From: Tomas Henzl <thenzl@redhat.com>
To: Sumit Saxena <sumit.saxena@avagotech.com>,
	jbottomley@parallels.com, hch@infradead.org,
	martin.petersen@oracle.com
Cc: linux-scsi@vger.kernel.org, Kashyap Desai <kashyap.desai@avagotech.com>
Subject: Re: [PATCH 09/15] megaraid_sas: Dual Queue depth support
Date: Wed, 20 Jan 2016 15:16:05 +0100	[thread overview]
Message-ID: <569F96A5.3080001@redhat.com> (raw)
In-Reply-To: <c7c1d7ab31105f2bf57fe20b326d2a5e@mail.gmail.com>

On 20.1.2016 15:09, Sumit Saxena wrote:
>> -----Original Message-----
>> From: Tomas Henzl [mailto:thenzl@redhat.com]
>> Sent: Wednesday, January 20, 2016 7:26 PM
>> To: Sumit Saxena; jbottomley@parallels.com; hch@infradead.org;
>> martin.petersen@oracle.com
>> Cc: linux-scsi@vger.kernel.org; Kashyap Desai
>> Subject: Re: [PATCH 09/15] megaraid_sas: Dual Queue depth support
>>
>> On 19.1.2016 14:44, Sumit Saxena wrote:
>>>> -----Original Message-----
>>>> From: Tomas Henzl [mailto:thenzl@redhat.com]
>>>> Sent: Tuesday, January 19, 2016 7:04 PM
>>>> To: Sumit Saxena; jbottomley@parallels.com; hch@infradead.org;
>>>> martin.petersen@oracle.com
>>>> Cc: linux-scsi@vger.kernel.org; kashyap.desai@avagotech.com
>>>> Subject: Re: [PATCH 09/15] megaraid_sas: Dual Queue depth support
>>>>
>>>> On 18.12.2015 14:27, Sumit Saxena wrote:
>>>>> This patch will add support for Dual Queue depth reported by firmware.
>>>>>
>>>>> Below are key points-
>>>>>
>>>>> 1. For iMR controllers, firmware will report two queue depths- 1.
>>> Controller
>>>> wide Queue depth 2. LDIO Queue depth(240).
>>>>> Ofcourse, Controller wide Queue depth will be greater among two.
>>>>> Using this new method, iMR can provide larger Queue depth(QD) for
>>>>> JBOD and limited QD for Virtual Disk(VD). This feature gives benefit
>>>>> for iMR
>>> product
>>>> which will be used for deployment with large number of JBOD and
>>>> limited number of VD on setup.
>>>>> 2. megaraid_sas driver will throttle Read write LDIOs based when RW
>>> LDIOs
>>>> reaches "LDIO Queue Depth".
>>>>> 3. This feature of dual queue depth can enabled/disabled via module
>>>> parameter. Default behavior is: Dual Queue depth is enabled.
>>>>> 4. Added sysfs parameter "ldio_outstanding" for user to read LDIO
>>> outstanding
>>>> at run time.
>>>>> Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
>>>>> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
>>>>> ---
>>>>>  drivers/scsi/megaraid/megaraid_sas.h        |    9 +++
>>>>>  drivers/scsi/megaraid/megaraid_sas_base.c   |   20 ++++++-
>>>>>  drivers/scsi/megaraid/megaraid_sas_fusion.c |   89
>>>> ++++++++++++++++++++++++---
>>>>>  3 files changed, 108 insertions(+), 10 deletions(-)
>>>>>
>>>>> diff --git a/drivers/scsi/megaraid/megaraid_sas.h
>>>>> b/drivers/scsi/megaraid/megaraid_sas.h
>>>>> index c539516..4595ef4 100644
>>>>> --- a/drivers/scsi/megaraid/megaraid_sas.h
>>>>> +++ b/drivers/scsi/megaraid/megaraid_sas.h
>>>>> @@ -1353,6 +1353,12 @@ enum DCMD_TIMEOUT_ACTION {
>>>>>  	KILL_ADAPTER = 1,
>>>>>  	IGNORE_TIMEOUT = 2,
>>>>>  };
>>>>> +
>>>>> +enum FW_BOOT_CONTEXT {
>>>>> +	PROBE_CONTEXT = 0,
>>>>> +	OCR_CONTEXT = 1,
>>>>> +};
>>>>> +
>>>>>  /* Frame Type */
>>>>>  #define IO_FRAME				0
>>>>>  #define PTHRU_FRAME				1
>>>>> @@ -2038,6 +2044,8 @@ struct megasas_instance {
>>>>>  	u16 max_fw_cmds;
>>>>>  	u16 max_mfi_cmds;
>>>>>  	u16 max_scsi_cmds;
>>>>> +	u16 ldio_threshold;
>>>>> +	u16 cur_can_queue;
>>>>>  	u32 max_sectors_per_req;
>>>>>  	struct megasas_aen_event *ev;
>>>>>
>>>>> @@ -2068,6 +2076,7 @@ struct megasas_instance {
>>>>>  	u32 fw_support_ieee;
>>>>>
>>>>>  	atomic_t fw_outstanding;
>>>>> +	atomic_t ldio_outstanding;
>>>>>  	atomic_t fw_reset_no_pci_access;
>>>>>
>>>>>  	struct megasas_instance_template *instancet; diff --git
>>>>> a/drivers/scsi/megaraid/megaraid_sas_base.c
>>>>> b/drivers/scsi/megaraid/megaraid_sas_base.c
>>>>> index 3454c5e..edc26fb 100644
>>>>> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
>>>>> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
>>>>> @@ -96,6 +96,10 @@ int rdpq_enable = 1;  module_param(rdpq_enable,
>>>>> int, S_IRUGO);  MODULE_PARM_DESC(rdpq_enable, " Allocate reply queue
>>>>> in chunks for large queue depth enable/disbale Default:
>>>>> disable(0)");
>>>>>
>>>>> +unsigned int dual_qdepth_disable;
>>>>> +module_param(dual_qdepth_disable, int, S_IRUGO);
>>>>> +MODULE_PARM_DESC(dual_qdepth_disable, "Disable dual queue depth
>>>>> +feature. Default: 0");
>>>>> +
>>>>>  MODULE_LICENSE("GPL");
>>>>>  MODULE_VERSION(MEGASAS_VERSION);
>>>>>  MODULE_AUTHOR("megaraidlinux.pdl@avagotech.com");
>>>>> @@ -1977,7 +1981,7 @@
>> megasas_check_and_restore_queue_depth(struct
>>>> megasas_instance *instance)
>>>>>  		spin_lock_irqsave(instance->host->host_lock, flags);
>>>>>  		instance->flag &= ~MEGASAS_FW_BUSY;
>>>>>
>>>>> -		instance->host->can_queue = instance->max_scsi_cmds;
>>>>> +		instance->host->can_queue = instance->cur_can_queue;
>>>>>  		spin_unlock_irqrestore(instance->host->host_lock, flags);
>>>>>  	}
>>>>>  }
>>>>> @@ -2942,6 +2946,16 @@ megasas_page_size_show(struct device *cdev,
>>>>>  	return snprintf(buf, PAGE_SIZE, "%ld\n", (unsigned long)PAGE_SIZE
>>> -
>>>>> 1);  }
>>>>>
>>>>> +static ssize_t
>>>>> +megasas_ldio_outstanding_show(struct device *cdev, struct
>>> device_attribute
>>>> *attr,
>>>>> +	char *buf)
>>>>> +{
>>>>> +	struct Scsi_Host *shost = class_to_shost(cdev);
>>>>> +	struct megasas_instance *instance = (struct megasas_instance
>>>>> +*)shost->hostdata;
>>>>> +
>>>>> +	return snprintf(buf, PAGE_SIZE, "%d\n",
>>>>> +atomic_read(&instance->ldio_outstanding));
>>>>> +}
>>>>> +
>>>>>  static DEVICE_ATTR(fw_crash_buffer, S_IRUGO | S_IWUSR,
>>>>>  	megasas_fw_crash_buffer_show, megasas_fw_crash_buffer_store);
>>>>> static DEVICE_ATTR(fw_crash_buffer_size, S_IRUGO, @@ -2950,12
>>>>> +2964,15 @@ static DEVICE_ATTR(fw_crash_state, S_IRUGO | S_IWUSR,
>>>>>  	megasas_fw_crash_state_show, megasas_fw_crash_state_store);
>>>> static
>>>>> DEVICE_ATTR(page_size, S_IRUGO,
>>>>>  	megasas_page_size_show, NULL);
>>>>> +static DEVICE_ATTR(ldio_outstanding, S_IRUGO,
>>>>> +	megasas_ldio_outstanding_show, NULL);
>>>>>
>>>>>  struct device_attribute *megaraid_host_attrs[] = {
>>>>>  	&dev_attr_fw_crash_buffer_size,
>>>>>  	&dev_attr_fw_crash_buffer,
>>>>>  	&dev_attr_fw_crash_state,
>>>>>  	&dev_attr_page_size,
>>>>> +	&dev_attr_ldio_outstanding,
>>>>>  	NULL,
>>>>>  };
>>>>>
>>>>> @@ -4750,6 +4767,7 @@ megasas_init_adapter_mfi(struct
>>>>> megasas_instance
>>>> *instance)
>>>>>  		sema_init(&instance->ioctl_sem,
>>>> (MEGASAS_MFI_IOCTL_CMDS));
>>>>>  	}
>>>>>
>>>>> +	instance->cur_can_queue = instance->max_scsi_cmds;
>>>>>  	/*
>>>>>  	 * Create a pool of commands
>>>>>  	 */
>>>>> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
>>>>> b/drivers/scsi/megaraid/megaraid_sas_fusion.c
>>>>> index 9ad779d..7cc7806 100644
>>>>> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
>>>>> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
>>>>> @@ -92,6 +92,7 @@ void megasas_start_timer(struct megasas_instance
>>>> *instance,
>>>>>  			 void *fn, unsigned long interval);  extern struct
>>>>> megasas_mgmt_info megasas_mgmt_info;  extern int resetwaittime;
>>>>> +extern unsigned int dual_qdepth_disable;
>>>>>  static void megasas_free_rdpq_fusion(struct megasas_instance
>>>>> *instance);  static void megasas_free_reply_fusion(struct
>>>>> megasas_instance *instance);
>>>>>
>>>>> @@ -208,6 +209,67 @@ megasas_fire_cmd_fusion(struct
>> megasas_instance
>>>>> *instance,  }
>>>>>
>>>>>  /**
>>>>> + * megasas_fusion_update_can_queue -	Do all Adapter Queue depth
>>>> related calculations here
>>>>> + * @instance:
>>>> 	Adapter soft state
>>>>> + * fw_boot_context:
>>> Whether this
>>>> function called during probe or after OCR
>>>>> + *
>>>>> + * This function is only for fusion controllers.
>>>>> + * Update host can queue, if firmware downgrade max supported
>>> firmware
>>>> commands.
>>>>> + * Firmware upgrade case will be skiped because underlying firmware
>>>>> +has
>>>>> + * more resource than exposed to the OS.
>>>>> + *
>>>>> + */
>>>>> +static void
>>>>> +megasas_fusion_update_can_queue(struct megasas_instance *instance,
>>>>> +int fw_boot_context) {
>>>>> +	u16 cur_max_fw_cmds = 0;
>>>>> +	u16 ldio_threshold = 0;
>>>>> +	struct megasas_register_set __iomem *reg_set;
>>>>> +
>>>>> +	reg_set = instance->reg_set;
>>>>> +
>>>>> +	cur_max_fw_cmds = readl(&instance->reg_set-
>>>>> outbound_scratch_pad_3)
>>>>> +& 0x00FFFF;
>>>>> +
>>>>> +	if (dual_qdepth_disable || !cur_max_fw_cmds)
>>>>> +		cur_max_fw_cmds = instance->instancet-
>>>>> read_fw_status_reg(reg_set) & 0x00FFFF;
>>>>> +	else
>>>>> +		ldio_threshold =
>>>>> +			(instance->instancet->read_fw_status_reg(reg_set)
>>> &
>>>> 0x00FFFF) -
>>>>> +MEGASAS_FUSION_IOCTL_CMDS;
>>>>> +
>>>>> +	dev_info(&instance->pdev->dev,
>>>>> +			"Current firmware maximum commands: %d\t LDIO
>>>> thershold: %d\n",
>>>>
>>>> a typo in "thershold"
>>>>
>>>>> +			cur_max_fw_cmds, ldio_threshold);
>>>>> +
>>>>> +	if (fw_boot_context == OCR_CONTEXT) {
>>>>> +		cur_max_fw_cmds = cur_max_fw_cmds - 1;
>>>>> +		if (cur_max_fw_cmds <= instance->max_fw_cmds) {
>>>> probably '<' instead of '<=" could be here ?
>>>>
>>>>> +			instance->cur_can_queue =
>>>>> +				cur_max_fw_cmds -
>>>> (MEGASAS_FUSION_INTERNAL_CMDS +
>>>>> +
>>>> 	MEGASAS_FUSION_IOCTL_CMDS);
>>>>> +			instance->host->can_queue = instance-
>>>>> cur_can_queue;
>>>>> +			instance->ldio_threshold = ldio_threshold;
>>>>> +		}
>>>>> +	} else {
>>>>> +		instance->max_fw_cmds = cur_max_fw_cmds;
>>>>> +		instance->ldio_threshold = ldio_threshold;
>>>>> +
>>>>> +		if (!instance->is_rdpq)
>>>>> +			instance->max_fw_cmds = min_t(u16, instance-
>>>>> max_fw_cmds, 1024);
>>>>> +
>>>>> +		/*
>>>>> +		* Reduce the max supported cmds by 1. This is to ensure
>>> that
>>>> the
>>>>> +		* reply_q_sz (1 more than the max cmd that driver may
>>> send)
>>>>> +		* does not exceed max cmds that the FW can support
>>>>> +		*/
>>>>> +		instance->max_fw_cmds = instance->max_fw_cmds-1;
>>>>> +
>>>>> +		instance->max_scsi_cmds = instance->max_fw_cmds -
>>>>> +				(MEGASAS_FUSION_INTERNAL_CMDS +
>>>>> +				MEGASAS_FUSION_IOCTL_CMDS);
>>>>> +		instance->cur_can_queue = instance->max_scsi_cmds;
>>>>> +	}
>>>>> +}
>>>>> +/**
>>>>>   * megasas_free_cmds_fusion -	Free all the cmds in the free cmd
>>> pool
>>>>>   * @instance:		Adapter soft state
>>>>>   */
>>>>> @@ -736,6 +798,8 @@ megasas_ioc_init_fusion(struct megasas_instance
>>>> *instance)
>>>>>  		drv_ops->mfi_capabilities.support_ext_io_size = 1;
>>>>>
>>>>>  	drv_ops->mfi_capabilities.support_fp_rlbypass = 1;
>>>>> +	if (!dual_qdepth_disable)
>>>>> +		drv_ops->mfi_capabilities.support_ext_queue_depth = 1;
>>>>>
>>>>>  	/* Convert capability to LE32 */
>>>>>  	cpu_to_le32s((u32
>>>>> *)&init_frame->driver_operations.mfi_capabilities);
>>>>> @@ -1151,15 +1215,7 @@ megasas_init_adapter_fusion(struct
>>>>> megasas_instance *instance)
>>>>>
>>>>>  	reg_set = instance->reg_set;
>>>>>
>>>>> -	/*
>>>>> -	 * Get various operational parameters from status register
>>>>> -	 */
>>>>> -	instance->max_fw_cmds =
>>>>> -		instance->instancet->read_fw_status_reg(reg_set) &
>>> 0x00FFFF;
>>>>> -	dev_info(&instance->pdev->dev,
>>>>> -		"firmware support max fw cmd\t: (%d)\n", instance-
>>>>> max_fw_cmds);
>>>>> -	if (!instance->is_rdpq)
>>>>> -		instance->max_fw_cmds = min_t(u16, instance-
>>>>> max_fw_cmds, 1024);
>>>>> +	megasas_fusion_update_can_queue(instance, PROBE_CONTEXT);
>>>>>
>>>>>  	/*
>>>>>  	 * Reduce the max supported cmds by 1. This is to ensure that the
>>> @@
>>>>> -2117,6 +2173,15 @@ megasas_build_and_issue_cmd_fusion(struct
>>>>> megasas_instance *instance,
>>>>>
>>>>>  	fusion = instance->ctrl_context;
>>>>>
>>>>> +	if (megasas_cmd_type(scmd) == READ_WRITE_LDIO) {
>>>>> +		if (instance->ldio_threshold &&
>>>>> +			(atomic_read(&instance->ldio_outstanding) >=
>>>>> +			instance->ldio_threshold))
>>>> This test above won't you protect when several processes read the
>>>> same
>>> value
>>>> in parallel, so it may happen that you get over the limit set for
>>> ldio_threshold.
>>>> (You might use instead a construction with atomic_dec_and_test for
>>> example)
>>>
>>> Agree..I will fix this and send updated patch.
>> In addition to my previous comments - I'm no sure if the idea of two
>> queues
>> doesn't have some pitfalls - your parallel queue is based on returning
>> commands
>> to the midlayer with SCSI_MLQUEUE_DEVICE_BUSY - that makes it repeatedly
>> post it to your queue again. Isn't there a performance loss with Virtual
>> Disks ?
> Yes this is already covered internally, there would be perf penalty with VDs
> in configuration but this feature will be turned on based on firmware
> settings and that specific firmware deployment has primary purpose
> of increasing JBOD performance. This focuses on firmware deployment with
> less VDs(or no) and more JBODs in configuration.

OK, so it is switched off by default in the firmware and the user
and an educated user can switch it on ? if so, it's fine for me.

>
> Thanks,
> Sumit
>
>>
>>>> tomash


  reply	other threads:[~2016-01-20 14:16 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-18 13:26 [PATCH 00/15] megaraid_sas: Updates for scsi-next Sumit Saxena
2015-12-18 13:26 ` [PATCH 01/15] megaraid_sas: Do not allow PCI access during OCR Sumit Saxena
2016-01-11 17:02   ` Tomas Henzl
2015-12-18 13:26 ` [PATCH 02/15] megaraid_sas: MFI IO timeout handling Sumit Saxena
2016-01-11 17:02   ` Tomas Henzl
2015-12-18 13:26 ` [PATCH 03/15] megaraid_sas: Syncing request flags macro names with firmware Sumit Saxena
2016-01-11 17:03   ` Tomas Henzl
2015-12-18 13:26 ` [PATCH 04/15] megaraid_sas: Task management support Sumit Saxena
2016-01-11 17:03   ` Tomas Henzl
2016-01-14 12:04     ` Sumit Saxena
2015-12-18 13:26 ` [PATCH 05/15] megaraid_sas: Update device Queue depth based on interface type Sumit Saxena
2016-01-12 14:16   ` Tomas Henzl
2016-01-14 11:48     ` Sumit Saxena
2015-12-18 13:26 ` [PATCH 06/15] megaraid_sas: Fastpath region lock bypass Sumit Saxena
2016-01-12 14:44   ` Tomas Henzl
2015-12-18 13:27 ` [PATCH 07/15] megaraid_sas: Reply Descriptor Post Queue(RDPQ) support Sumit Saxena
2015-12-18 14:49   ` [PATCH] megaraid_sas: fix kzalloc-simple.cocci warnings kbuild test robot
2015-12-18 14:49   ` [PATCH 07/15] megaraid_sas: Reply Descriptor Post Queue(RDPQ) support kbuild test robot
2016-01-14 17:38   ` Tomas Henzl
2016-01-27 18:15     ` Sumit Saxena
2015-12-18 13:27 ` [PATCH 08/15] megaraid_sas: Code optimization build_and_issue_cmd return-type Sumit Saxena
2016-01-14 18:05   ` Tomas Henzl
2015-12-18 13:27 ` [PATCH 09/15] megaraid_sas: Dual Queue depth support Sumit Saxena
2016-01-19 13:34   ` Tomas Henzl
2016-01-19 13:44     ` Sumit Saxena
2016-01-20 13:55       ` Tomas Henzl
2016-01-20 14:09         ` Sumit Saxena
2016-01-20 14:16           ` Tomas Henzl [this message]
2016-01-20 15:08             ` Sumit Saxena
2016-01-20 16:00               ` Tomas Henzl
2016-01-27  2:02             ` Martin K. Petersen
2016-01-27  7:09               ` Sumit Saxena
2015-12-18 13:27 ` [PATCH 10/15] megaraid_sas: IO throttling support Sumit Saxena
2016-01-19 13:38   ` Tomas Henzl
2016-01-28  7:18     ` Sumit Saxena
2015-12-18 13:27 ` [PATCH 11/15] megaraid_sas: Make adprecovery variable atomic Sumit Saxena
2016-01-19 13:52   ` Tomas Henzl
2016-01-28  8:30     ` Sumit Saxena
2015-12-18 13:27 ` [PATCH 12/15] megaraid_sas: MFI adapter's OCR changes Sumit Saxena
2016-01-19 14:22   ` Tomas Henzl
2016-01-28 11:12     ` Sumit Saxena
2015-12-18 13:27 ` [PATCH 13/15] megaraid_sas: Introduce module parameter for SCSI command-timeout Sumit Saxena
2016-01-19 14:57   ` Tomas Henzl
2016-01-28 11:17     ` Sumit Saxena
2015-12-18 13:27 ` [PATCH 14/15] megaraid_sas: SPERC OCR changes Sumit Saxena
2016-01-19 15:14   ` Tomas Henzl
2015-12-18 13:27 ` [PATCH 15/15] megaraid_sas: SPERC boot driver reorder Sumit Saxena
2015-12-18 14:05   ` Christoph Hellwig
2016-01-08  7:07     ` Sumit Saxena
2016-01-12  5:26     ` Sumit Saxena

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