Subject: Re: [PATCH v1 2/3] scsi: ufs: Optimize host lock on transfer requests send/compl paths

From: Stanley Chu <[email-masked]>
Date: Thu, 3 Jun 2021 10:54:25 +0800

Hi Can,

On Mon, 2021-05-24 at 01:36 -0700, Can Guo wrote:
> Current UFS IRQ handler is completely wrapped by host lock, and because
> ufshcd_send_command() is also protected by host lock, when IRQ handler
> fires, not only the CPU running the IRQ handler cannot send new requests,
> the rest CPUs can neither. Move the host lock wrapping the IRQ handler into
> specific branches, i.e., ufshcd_uic_cmd_compl(), ufshcd_check_errors(),
> ufshcd_tmc_handler() and ufshcd_transfer_req_compl(). Meanwhile, to further
> reduce occpuation of host lock in ufshcd_transfer_req_compl(), host lock is
> no longer required to call __ufshcd_transfer_req_compl(). As per test, the
> optimization can bring considerable gain to random read/write performance.
> 
> Cc: Stanley Chu <[email-masked]>
> Co-developed-by: Asutosh Das <[email-masked]>
> Signed-off-by: Asutosh Das <[email-masked]>
> Signed-off-by: Can Guo <[email-masked]>

According to my test, the performance indeed has impressive improvement
with this series!

Reviewed-by: Stanley Chu <[email-masked]>

>  #endif
>  	bool req_abort_skip;
> -	bool in_use;
>  };
>  /**

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