From: "Levin, Alexander (Sasha Levin)" <alexander.levin@one.verizon.com>
To: Mark Brown <broonie@kernel.org>
Cc: "Levin,
Alexander (Sasha Levin)" <alexander.levin@one.verizon.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
Jiada Wang <jiada_wang@mentor.com>
Subject: Re: [PATCH AUTOSEL for-4.9 04/53] spi: imx: adjust watermark level according to transfer length
Date: Wed, 8 Nov 2017 21:39:11 +0000 [thread overview]
Message-ID: <20171108213909.mm4mnzga3vic3sbc@sasha-lappy> (raw)
In-Reply-To: <20171108205752.awsx5rzo4aecfl7i@sirena.co.uk>
On Wed, Nov 08, 2017 at 08:57:52PM +0000, Mark Brown wrote:
>On Wed, Nov 08, 2017 at 08:49:55PM +0000, Levin, Alexander (Sasha Levin) wrote:
>> From: Jiada Wang <jiada_wang@mentor.com>
>>
>> [ Upstream commit 66459c5a50a787c474b734b586328f7111ab6df0 ]
>>
>> Previously DMA watermark level is configured to fifosize/2,
>> DMA mode can be used only when transfer length can be divided
>> by 'watermark level * bpw', which makes DMA mode not pratical.
>>
>> This patch adjusts watermark level to largest number (no bigger
>> than fifosize/2) which can divide 'tranfer length / bpw' for
>> each transfer.
>
>This seems like an optimization not a bug fix...
Hm, is it? I read it as "DMA is not being used at all even though we
thought we're using it".
Yes, the impact is "just" performance, but doesn't it result in quite
a significat impact?
--
Thanks,
Sasha
next prev parent reply other threads:[~2017-11-08 21:40 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-08 20:49 [PATCH AUTOSEL for-4.9 01/53] extcon: Remove potential problem when calling extcon_register_notifier() Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 03/53] fm10k: request reset when mbx->state changes Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 02/53] extcon: palmas: Check the parent instance to prevent the NULL Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 05/53] ARM: dts: Fix compatible for ti81xx uarts for 8250 Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 04/53] spi: imx: adjust watermark level according to transfer length Levin, Alexander (Sasha Levin)
2017-11-08 20:57 ` Mark Brown
2017-11-08 21:39 ` Levin, Alexander (Sasha Levin) [this message]
2017-11-08 22:11 ` Mark Brown
2017-11-08 22:48 ` Levin, Alexander (Sasha Levin)
2017-11-08 23:11 ` Mark Brown
2017-11-09 0:00 ` Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 06/53] ARM: dts: Fix am335x and dm814x scm syscon to probe children Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 08/53] ARM: dts: Fix omap3 off mode pull defines Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 09/53] ARM: dts: omap5-uevm: Allow bootloader to configure USB Ethernet MAC Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 07/53] ARM: OMAP2+: Fix init for multiple quirks for the same SoC Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 10/53] ata: ATA_BMDMA should depend on HAS_DMA Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 12/53] ata: SATA_MV " Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 11/53] ata: SATA_HIGHBANK " Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 16/53] igb: Fix hw_dbg logging in igb_update_flash_i210 Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 15/53] igb: close/suspend race in netif_device_detach Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 14/53] igb: reset the PHY before reading the PHY ID Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 13/53] drm/sti: sti_vtg: Handle return NULL error from devm_ioremap_nocache Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 17/53] scsi: ufs-qcom: Fix module autoload Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 20/53] staging: rtl8188eu: fix incorrect ERROR tags from logs Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 19/53] tcp: provide timestamps for partial writes Levin, Alexander (Sasha Levin)
2017-11-08 20:49 ` [PATCH AUTOSEL for-4.9 18/53] scsi: ufs: add capability to keep auto bkops always enabled Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 24/53] scsi: lpfc: Correct host name in symbolic_name field Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 23/53] scsi: lpfc: FCoE VPort enable-disable does not bring up the VPort Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 22/53] scsi: lpfc: Add missing memory barrier Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 21/53] x86/irq, trace: Add __irq_entry annotation to x86's platform IRQ handlers Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 27/53] rtc: rx8010: change lock mechanism Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 26/53] scsi: lpfc: Clear the VendorVersion in the PLOGI/PLOGI ACC payload Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 25/53] scsi: lpfc: Correct issue leading to oops during link reset Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 28/53] power: supply: axp288_fuel_gauge: Read 15 bit values 2 registers at a time Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 32/53] drm/omap: panel-sony-acx565akm.c: Add MODULE_ALIAS Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 29/53] power: supply: axp288_fuel_gauge: Read 12 bit values 2 registers at a time Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 30/53] ALSA: vx: Don't try to update capture stream before running Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 31/53] ALSA: vx: Fix possible transfer overflow Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 36/53] ALSA: hda/realtek - Add new codec ID ALC299 Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 33/53] backlight: lcd: Fix race condition during register Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 35/53] gpu: drm: mgag200: mgag200_main:- Handle error from pci_iomap Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 34/53] backlight: adp5520: Fix error handling in adp5520_bl_probe() Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 40/53] ixgbe: handle close/suspend race with netif_device_detach/present Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 39/53] ixgbe: fix AER error handling Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 38/53] ixgbe: Configure advertised speeds correctly for KR/KX backplane Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 37/53] arm64: dts: NS2: reserve memory for Nitro firmware Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 42/53] ixgbe: Reduce I2C retry count on X550 devices Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 43/53] ixgbe: add mask for 64 RSS queues Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 41/53] ixgbe: Fix reporting of 100Mb capability Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 44/53] ixgbe: do not disable FEC from the driver Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 49/53] MIPS: init: Ensure bootmem does not corrupt reserved memory Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 45/53] staging: rtl8712: fixed little endian problem Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 47/53] staging: greybus: add host device function pointer checks Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 48/53] MIPS: End asm function prologue macros with .insn Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 46/53] staging: wilc1000: Fix endian sparse warning Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 52/53] MIPS: Netlogic: Exclude netlogic,xlp-pic code from XLR builds Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 53/53] MIPS: Use Makefile.postlink to insert relocations into vmlinux Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 51/53] MIPS: traps: Ensure L1 & L2 ECC checking match for CM3 systems Levin, Alexander (Sasha Levin)
2017-11-08 20:50 ` [PATCH AUTOSEL for-4.9 50/53] MIPS: init: Ensure reserved memory regions are not added to bootmem Levin, Alexander (Sasha Levin)
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