Messages in this thread | | | Date | Wed, 02 Jun 2021 10:14:39 +0800 | From | Can Guo <> | Subject | Re: [PATCH v1 2/3] scsi: ufs: Optimize host lock on transfer requests send/compl paths |
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Hi Bean,
On 2021-06-01 00:04, Bean Huo wrote: > 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 <stanley.chu@mediatek.com> >> >> Co-developed-by: Asutosh Das <asutoshd@codeaurora.org> >> >> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org> >> >> Signed-off-by: Can Guo <cang@codeaurora.org> > > Can, > The patch looks good to me. > I did a UFS queue limitation test before, observed that once the queue > is full, then the active task number in the queue will get down. For > the Nvme, the scenario is the same. You can refer to the slide 23, and > slide 24 in the pdf: > https://elinux.org/images/6/6c/Linux_Storage_System_Bottleneck_Exploration_V0.3.pdf > I don't know if your patch can fix this > issue.
I've studied these slides made by you many times, it is really good. I will do some study later on this. Thanks for the slides.
> > Unfortunately, I cannot verify UTRLCNR usage flow since my platform is > v2.1. But at least my test can prove that the patch doesn't impact the > legacy(UFSHCI is less than v3.0) doorbell usage flow. >
Thanks for your time :).
Regards, Can Guo.
> Reviewed-by: Bean Huo <beanhuo@micron.com> > > > Bean
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