Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1738773
| From | Sricharan R <sricharan@codeaurora.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v4] dmaengine: qcom-bam: Process multiple pending descriptors |
| Date | 2017-09-25 09:00 +0200 |
| Message-ID | <utvx0-2Kk-5@gated-at.bofh.it> (permalink) |
| References | <ujtPQ-78t-5@gated-at.bofh.it> <utuUh-2ui-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 9/25/2017 11:50 AM, Vinod Koul wrote: > On Mon, Aug 28, 2017 at 08:30:24PM +0530, Sricharan R wrote: >> The bam dmaengine has a circular FIFO to which we >> add hw descriptors that describes the transaction. >> The FIFO has space for about 4096 hw descriptors. >> >> Currently we add one descriptor and wait for it to >> complete with interrupt and then add the next pending >> descriptor. In this way, the FIFO is underutilized >> since only one descriptor is processed at a time, although >> there is space in FIFO for the BAM to process more. >> >> Instead keep adding descriptors to FIFO till its full, >> that allows BAM to continue to work on the next descriptor >> immediately after signalling completion interrupt for the >> previous descriptor. >> >> Also when the client has not set the DMA_PREP_INTERRUPT for >> a descriptor, then do not configure BAM to trigger a interrupt >> upon completion of that descriptor. This way we get a interrupt >> only for the descriptor for which DMA_PREP_INTERRUPT was >> requested and there signal completion of all the previous completed >> descriptors. So we still do callbacks for all requested descriptors, >> but just that the number of interrupts are reduced. >> >> CURRENT: >> >> ------ ------- --------------- >> |DES 0| |DESC 1| |DESC 2 + INT | >> ------ ------- --------------- >> | | | >> | | | >> INTERRUPT: (INT) (INT) (INT) >> CALLBACK: (CB) (CB) (CB) >> >> MTD_SPEEDTEST READ PAGE: 3560 KiB/s >> MTD_SPEEDTEST WRITE PAGE: 2664 KiB/s >> IOZONE READ: 2456 KB/s >> IOZONE WRITE: 1230 KB/s >> >> bam dma interrupts (after tests): 96508 >> >> CHANGE: >> >> ------ ------- ------------- >> |DES 0| |DESC 1 |DESC 2 + INT | >> ------ ------- -------------- >> | >> | >> (INT) >> (CB for 0, 1, 2) >> >> MTD_SPEEDTEST READ PAGE: 3860 KiB/s >> MTD_SPEEDTEST WRITE PAGE: 2837 KiB/s >> IOZONE READ: 2677 KB/s >> IOZONE WRITE: 1308 KB/s >> >> bam dma interrupts (after tests): 58806 > > Applied, thanks. > > Sorry for the delay, bad timing I guess :) > Sure np, Thanks for that. Regards, Sricharan -- "QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread
Re: [PATCH v4] dmaengine: qcom-bam: Process multiple pending descriptors Vinod Koul <vinod.koul@intel.com> - 2017-09-25 08:20 +0200 Re: [PATCH v4] dmaengine: qcom-bam: Process multiple pending descriptors Sricharan R <sricharan@codeaurora.org> - 2017-09-25 09:00 +0200
csiph-web