From: Avri Altman <Avri.Altman@wdc.com> To: Asutosh Das <email@example.com>, "firstname.lastname@example.org" <email@example.com>, "firstname.lastname@example.org" <email@example.com>, "firstname.lastname@example.org" <email@example.com> Cc: "firstname.lastname@example.org" <email@example.com> Subject: RE: [<RFC RESEND PATCH v2> 0/3] WriteBooster Feature Support Date: Thu, 26 Mar 2020 21:53:25 +0000 Message-ID: <SN6PR04MB46401B509D68CAE9C4828B0FFCCF0@SN6PR04MB4640.namprd04.prod.outlook.com> (raw) In-Reply-To: <firstname.lastname@example.org> Hi, The code looks good to me and I encourage you to submit your patches. I just want to make some general remarks: - The way you use the clock scaling to set WB on/off, is IMO, an elegant design choice. - You should add a platform capability for WB - As for setting user space configuration options - I think you've got it wrong. You should read it from bSupportedWriteBoosterBufferUserSpaceReductionTypes (offset 0x55 in the device descriptor). This is a configurable parameter that the chipset vendor control and can set during provisioning. - I agree with your approach toward flush during runtime suspend (keep-vcc-on): it is the host's interest to assist the device with some extra idle time if needed for WB flush. This way you will assure consistent write performance. Thanks, Avri > > > Still a RFC patch, because I'm still expecting some comments > on the design. > > v1 -> v2: > - Addressed comments on v1 > > - Supports shared buffer mode only > > - Didn't use exception event as suggested. > The reason being while testing I saw that the WriteBooster > available buffer remains at 0x1 for a longer time if flush is > enabled all the time as compared to an event-based enablement. > This essentially means that writes go to the WriteBooster buffer > more. Spec says that the if flush is enabled, the device would > flush when it sees the command queue empty. So I guess that'd trigger > flush more than an event based approach. > Anyway the Vcc would be turned-off during system suspend, so flush > would stop anyway. > In this patchset, I never turn-off flush. > Hence the RFC. > > Asutosh Das (3): > scsi: ufs: add write booster feature support > ufs-qcom: scsi: configure write booster type > ufs: sysfs: add sysfs entries for write booster > > drivers/scsi/ufs/ufs-qcom.c | 7 ++ > drivers/scsi/ufs/ufs-sysfs.c | 39 ++++++- > drivers/scsi/ufs/ufs.h | 37 ++++++- > drivers/scsi/ufs/ufshcd.c | 238 > ++++++++++++++++++++++++++++++++++++++++++- > drivers/scsi/ufs/ufshcd.h | 9 ++ > 5 files changed, 324 insertions(+), 6 deletions(-) > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a > Linux Foundation Collaborative Project.
prev parent reply index Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-21 0:59 Asutosh Das 2020-03-21 0:59 ` [<RFC RESEND PATCH v2> 1/3] scsi: ufs: add write booster feature support Asutosh Das 2020-03-21 0:59 ` [<RFC RESEND PATCH v2> 2/3] ufs-qcom: scsi: configure write booster type Asutosh Das 2020-03-21 0:59 ` [<RFC RESEND PATCH v2> 3/3] ufs: sysfs: add sysfs entries for write booster Asutosh Das 2020-03-26 21:53 ` Avri Altman [this message]
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