Hi, this list moved to linux-omap@xxxxxxxxxxxxxxx ;-) On Thu, May 15, 2008 at 4:25 PM, Kumar, Purushotam <purushotam@xxxxxx> wrote: > This patch will increase performance significantly. In my testing with a SD Extreme III high speed 2GB SD card using FAT file system on OMAP35X TI EVM, write speed has improved by 2x whereas read speed has improved by 3 times for MMCSD when CONFIG_MMC_BLOCK_BOUNCE is enabled. It is supposed that larger/bounce buffers will be used by mmc core if CONFIG_MMC_BLOCK_BOUNCE is defined. But, in the mmc core, size of buffer is set to mmc->max_req_size if mmc->max_req_size is smaller than MMC_QUEUE_BOUNCESZ i.e. bounce buffer size (which is 64KB). By default, mmc->max_req_size is set to 4K. So, buffers of 4K will be used instead of 64K even if CONFIG_MMC_BLOCK_BOUNCE is defined without this patch. This patches forces mmc core to use bounce buffer of size MMC_QUEUE_BOUNCESZ and so performance is increased. > > Signed-off-by: Purushotam Kumar <purushotam@xxxxxx> > --- > Index: linux-omap-2.6/drivers/mmc/host/omap_hsmmc.c > =================================================================== > --- linux-omap-2.6.orig/drivers/mmc/host/omap_hsmmc.c > +++ linux-omap-2.6/drivers/mmc/host/omap_hsmmc.c > @@ -782,6 +782,15 @@ static int __init omap_mmc_probe(struct > else > host->dbclk_enabled = 1; > > +#ifdef CONFIG_MMC_BLOCK_BOUNCE > + mmc->max_phys_segs = 1; > + mmc->max_hw_segs = 1; > +#endif > + mmc->max_blk_size = 512; /* Block Length at max can be 1024 */ > + mmc->max_blk_count = 0xFFFF; /* No. of Blocks is 16 bits */ > + mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count; > + mmc->max_seg_size = mmc->max_req_size; > + > mmc->ocr_avail = mmc_slot(host).ocr_mask; > mmc->caps |= MMC_CAP_MULTIWRITE | MMC_CAP_MMC_HIGHSPEED | > MMC_CAP_SD_HIGHSPEED; Do you have any measurements results to share :-p -- Best Regards, Felipe Balbi felipebalbi@xxxxxxxxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
