Message-ID: <459befddaf0e9f9ad1f597f1037f82ba@mail.gmail.com>
Date:   Wed, 14 Dec 2016 16:54:19 -0500
From:   Sasikumar PC <sasikumar.pc@...adcom.com>
To:     Tomas Henzl <thenzl@...hat.com>, jejb@...nel.org, hch@...radead.org
Cc:     linux-scsi@...r.kernel.org,
        Sathya Prakash Veerichetty <sathya.prakash@...adcom.com>,
        linux-kernel@...r.kernel.org,
        Christopher Owens <christopher.owens@...adcom.com>,
        Kiran Kumar Kasturi <kiran-kumar.kasturi@...adcom.com>
Subject: RE: [PATCH V4 08/11] megaraid_sas: Enable or Disable Fast path based
 on the PCI Threshold Bandwidth

Hi Tomas,

Please see my response inline

Thanks
sasi

-----Original Message-----
From: Tomas Henzl [mailto:thenzl@...hat.com]
Sent: Friday, December 09, 2016 8:59 AM
To: Sasikumar Chandrasekaran; jejb@...nel.org; hch@...radead.org
Cc: linux-scsi@...r.kernel.org; Sathya.Prakash@...adcom.com;
linux-kernel@...r.kernel.org; christopher.owens@...adcom.com;
kiran-kumar.kasturi@...adcom.com
Subject: Re: [PATCH V4 08/11] megaraid_sas: Enable or Disable Fast path
based on the PCI Threshold Bandwidth

On 7.12.2016 00:00, Sasikumar Chandrasekaran wrote:
> Large SEQ IO workload should sent as non fast path commands
>
> This patch is depending on patch 7
>
> Signed-off-by: Sasikumar Chandrasekaran <sasikumar.pc@...adcom.com>
> ---
>  drivers/scsi/megaraid/megaraid_sas.h        |  8 +++++
>  drivers/scsi/megaraid/megaraid_sas_base.c   | 48
+++++++++++++++++++++++++++++
>  drivers/scsi/megaraid/megaraid_sas_fp.c     | 11 +++++--
>  drivers/scsi/megaraid/megaraid_sas_fusion.c | 20 +++++++-----
> drivers/scsi/megaraid/megaraid_sas_fusion.h |  2 +-
>  5 files changed, 78 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas.h
> b/drivers/scsi/megaraid/megaraid_sas.h
> index 3e087ab..eb5be2b 100644
> --- a/drivers/scsi/megaraid/megaraid_sas.h
> +++ b/drivers/scsi/megaraid/megaraid_sas.h
> @@ -1429,6 +1429,8 @@ enum FW_BOOT_CONTEXT {
>  #define MFI_1068_FW_HANDSHAKE_OFFSET		0x64
>  #define MFI_1068_FW_READY			0xDDDD0000
>
> +#define MEGASAS_RAID1_FAST_PATH_STATUS_CHECK_INTERVAL HZ
> +
>  #define MR_MAX_REPLY_QUEUES_OFFSET              0X0000001F
>  #define MR_MAX_REPLY_QUEUES_EXT_OFFSET          0X003FC000
>  #define MR_MAX_REPLY_QUEUES_EXT_OFFSET_SHIFT    14
> @@ -2101,6 +2103,10 @@ struct megasas_instance {
>  	atomic_t ldio_outstanding;
>  	atomic_t fw_reset_no_pci_access;
>
> +	atomic64_t bytes_wrote; /* used for raid1 fast path enable or
disable */
> +	atomic_t r1_write_fp_capable;

Is a an atomic variable needed for a just boolean variable?
Sasi - As we need to synchronize timer thread and IO issue threads,
With atomic, at any point of time the value will be definitive.
With boolean, it depends, the value could be in transit while
one thread is reading and other is writing.

> +
> +
>  	struct megasas_instance_template *instancet;
>  	struct tasklet_struct isr_tasklet;
>  	struct work_struct work_init;
> @@ -2143,6 +2149,7 @@ struct megasas_instance {
>  	long reset_flags;
>  	struct mutex reset_mutex;
>  	struct timer_list sriov_heartbeat_timer;
> +	struct timer_list r1_fp_hold_timer;
>  	char skip_heartbeat_timer_del;
>  	u8 requestorId;
>  	char PlasmaFW111;
> @@ -2159,6 +2166,7 @@ struct megasas_instance {
>  	bool is_ventura;
>  	bool msix_combined;
>  	u16 max_raid_mapsize;
> +	u64 pci_threshold_bandwidth; /* used to control the fp writes */
>  };
>  struct MR_LD_VF_MAP {
>  	u32 size;
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c
> b/drivers/scsi/megaraid/megaraid_sas_base.c
> index 8aafb59..899d25c 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -1940,6 +1940,9 @@ void megaraid_sas_kill_hba(struct megasas_instance
*instance)
>  	}
>  	/* Complete outstanding ioctls when adapter is killed */
>  	megasas_complete_outstanding_ioctls(instance);
> +	if (instance->is_ventura)
> +		del_timer_sync(&instance->r1_fp_hold_timer);
> +
>  }
>
>   /**
> @@ -2438,6 +2441,24 @@ void megasas_sriov_heartbeat_handler(unsigned
long instance_addr)
>  	}
>  }
>
> +/*Handler for disabling/enabling raid 1 fast paths*/ void
> +megasas_change_r1_fp_status(unsigned long instance_addr) {
> +	struct megasas_instance *instance =
> +			(struct megasas_instance *)instance_addr;
> +	if (atomic64_read(&instance->bytes_wrote) >=
> +					instance->pci_threshold_bandwidth)
{
> +
> +		atomic64_set(&instance->bytes_wrote, 0);
> +		atomic_set(&instance->r1_write_fp_capable, 0);
> +	} else {
> +		atomic64_set(&instance->bytes_wrote, 0);
> +		atomic_set(&instance->r1_write_fp_capable, 1);
> +	}
> +	mod_timer(&instance->r1_fp_hold_timer,
> +	 jiffies + MEGASAS_RAID1_FAST_PATH_STATUS_CHECK_INTERVAL);
> +}
> +
>  /**
>   * megasas_wait_for_outstanding -	Wait for all outstanding cmds
>   * @instance:				Adapter soft state
> @@ -5371,6 +5392,17 @@ static int megasas_init_fw(struct
megasas_instance *instance)
>  			instance->skip_heartbeat_timer_del = 1;
>  	}
>
> +	if (instance->is_ventura) {
> +		atomic64_set(&instance->bytes_wrote, 0);
> +		atomic_set(&instance->r1_write_fp_capable, 1);
> +		megasas_start_timer(instance,
> +			    &instance->r1_fp_hold_timer,
> +			    megasas_change_r1_fp_status,
> +
MEGASAS_RAID1_FAST_PATH_STATUS_CHECK_INTERVAL);
> +				dev_info(&instance->pdev->dev, "starting
the raid 1 fp timer with interval %d\n",
> +
MEGASAS_RAID1_FAST_PATH_STATUS_CHECK_INTERVAL);
> +	}
> +
>  	return 0;
>
>  fail_get_ld_pd_list:
> @@ -6161,6 +6193,9 @@ static void megasas_shutdown_controller(struct
megasas_instance *instance,
>  	if (instance->requestorId && !instance->skip_heartbeat_timer_del)
>  		del_timer_sync(&instance->sriov_heartbeat_timer);
>
> +	if (instance->is_ventura)
> +		del_timer_sync(&instance->r1_fp_hold_timer);
> +
>  	megasas_flush_cache(instance);
>  	megasas_shutdown_controller(instance, MR_DCMD_HIBERNATE_SHUTDOWN);
>
> @@ -6280,6 +6315,16 @@ static void megasas_shutdown_controller(struct
megasas_instance *instance,
>  	megasas_setup_jbod_map(instance);
>  	instance->unload = 0;
>
> +	if (instance->is_ventura) {
> +		atomic64_set(&instance->bytes_wrote, 0);
> +		atomic_set(&instance->r1_write_fp_capable, 1);
> +		megasas_start_timer(instance,
> +			    &instance->r1_fp_hold_timer,
> +			    megasas_change_r1_fp_status,
> +
MEGASAS_RAID1_FAST_PATH_STATUS_CHECK_INTERVAL);
> +	}
> +
> +
>  	/*
>  	 * Initiate AEN (Asynchronous Event Notification)
>  	 */
> @@ -6368,6 +6413,9 @@ static void megasas_detach_one(struct pci_dev
*pdev)
>  	if (instance->requestorId && !instance->skip_heartbeat_timer_del)
>  		del_timer_sync(&instance->sriov_heartbeat_timer);
>
> +	if (instance->is_ventura)
> +		del_timer_sync(&instance->r1_fp_hold_timer);
> +
>  	if (instance->fw_crash_state != UNAVAILABLE)
>  		megasas_free_host_crash_buffer(instance);
>  	scsi_remove_host(instance->host);
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fp.c
> b/drivers/scsi/megaraid/megaraid_sas_fp.c
> index a6957a3..7da4685 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fp.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fp.c
> @@ -197,14 +197,19 @@ void MR_PopulateDrvRaidMap(struct
> megasas_instance *instance)
>
>  	if (instance->max_raid_mapsize) {
>  		fw_map_dyn = fusion->ld_map[(instance->map_id & 1)];
> +		if (fw_map_dyn->pci_threshold_bandwidth)
> +			instance->pci_threshold_bandwidth =
> +			le64_to_cpu(fw_map_dyn->pci_threshold_bandwidth);
>  #if VD_EXT_DEBUG
>  		dev_dbg(&instance->pdev->dev,
>  		" raidMapSize 0x%x fw_map_dyn->descTableOffset 0x%x, "
> -		" descTableSize 0x%x descTableNumElements 0x%x\n",
> +		" descTableSize 0x%x descTableNumElements 0x%x, "
> +		" PCIThreasholdBandwidth %llu\n",
>  		le32_to_cpu(fw_map_dyn->raid_map_size),
>  		le32_to_cpu(fw_map_dyn->desc_table_offset),
>  		le32_to_cpu(fw_map_dyn->desc_table_size),
> -		le32_to_cpu(fw_map_dyn->desc_table_num_elements));
> +		le32_to_cpu(fw_map_dyn->desc_table_num_elements),
> +		instance->pci_threshold_bandwidth);
>  		dev_dbg(&instance->pdev->dev,
>  		"drv map %p ldCount %d\n", drv_map, fw_map_dyn->ld_count);
#endif
> @@ -434,6 +439,8 @@ void MR_PopulateDrvRaidMap(struct megasas_instance
*instance)
>  			sizeof(struct MR_DEV_HANDLE_INFO) *
>  			MAX_RAIDMAP_PHYSICAL_DEVICES);
>  	}
> +	if (instance->is_ventura && !instance->pci_threshold_bandwidth)
> +		instance->pci_threshold_bandwidth = ULLONG_MAX;
>  }
>
>  /*
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> index f968a23..5992153 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> @@ -95,6 +95,7 @@ void megasas_start_timer(struct megasas_instance
> *instance,  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);
> +void megasas_change_r1_fp_status(unsigned long instance_addr);
>
>
>
> @@ -2633,8 +2634,9 @@ void megasas_prepare_secondRaid1_IO(struct
megasas_instance *instance,
>  	*	to get new command
>  	*/
>  	if (cmd->is_raid_1_fp_write &&
> -		atomic_inc_return(&instance->fw_outstanding) >
> -			(instance->host->can_queue)) {
> +		(atomic_inc_return(&instance->fw_outstanding) >
> +			(instance->host->can_queue) ||
> +		(!atomic_read(&instance->r1_write_fp_capable)))) {
>  		megasas_fpio_to_ldio(instance, cmd, cmd->scmd);
>  		atomic_dec(&instance->fw_outstanding);
>  	} else if (cmd->is_raid_1_fp_write) { @@ -2643,17 +2645,19 @@ void

> megasas_prepare_secondRaid1_IO(struct megasas_instance *instance,
>  		megasas_prepare_secondRaid1_IO(instance, cmd, r1_cmd);
>  	}
>
> -
>  	/*
> -	 * Issue the command to the FW
> -	 */
> +	* Issue the command to the FW
> +	*/
> +	if (scmd->sc_data_direction == PCI_DMA_TODEVICE &&
instance->is_ventura)
> +		atomic64_add(scsi_bufflen(scmd), &instance->bytes_wrote);

You count the bytes written to the ventura card and based on that it is
asynchronously decided whether the r1_write_fp_capable bit is set in a
timer function.
Please explain what should be achieved with this.

Sasi - I am working on this and will be posting the update soon

Thanks,
Tomas




>
>  	megasas_fire_cmd_fusion(instance, req_desc, instance->is_ventura);
>
> -	if (r1_cmd)
> +	if (r1_cmd) {
> +		atomic64_add(scsi_bufflen(scmd), &instance->bytes_wrote);
>  		megasas_fire_cmd_fusion(instance, r1_cmd->request_desc,
> -				instance->is_ventura);
> -
> +			instance->is_ventura);
> +	}
>
>  	return 0;
>  }
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.h
> b/drivers/scsi/megaraid/megaraid_sas_fusion.h
> index c39c4ed..da05790 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.h
> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.h
> @@ -977,7 +977,7 @@ struct MR_FW_RAID_MAP_DYNAMIC {
>  	u32 desc_table_size;  /* Total Size of desc table */
>  	/* Total Number of elements in the desc table */
>  	u32 desc_table_num_elements;
> -	u64	reserved1;
> +	u64	pci_threshold_bandwidth;
>  	u32	reserved2[3];	/*future use */
>  	/* timeout value used by driver in FP IOs */
>  	u8 fp_pd_io_timeout_sec;

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