On Wed, May 06, 2009, Gadiyar, Anand wrote: > On Tue, May 5, 2009, Jarkko Lavinen wrote: > > On Tue, Apr 21, 2009 at 09:39:22AM +0200, ext Gadiyar, Anand wrote: > > > From: Anand Gadiyar <gadiyar@xxxxxx> > > > > > > OMAP: HSMMC: Do not enable buffer ready interrupt if using DMA > > > > > > This considerably reduces the number of interrupts during a transfer > > > and ought to result in some power saving. > > > > I tried the patch with reading from the raw mmc block device to > > /dev/null with dd (with bs 32k and 1M). I cannot see any > > difference in interrupt count from /proc/interrupts or in read > > speed. At least the patch works. Cpu was 34340es3. > > > > I also trid without the patch just disabling the Buffer > > Read/write Ready bits from INT_EN_MASK which is then written to > > both MMCHS_IE and MMCHS_ISE. Still no change in read speed nor > > mmc irq count. > > > > Cheers > > Jarkko Lavinen > > I discovered this while doing MMC writes. I did not check if there > was any difference during a read. I notice you have only tested with > MMC reads. > > Here's what I get with and without the patch. > > - Anand Any comments on this? Is it safe to merge? Thanks, Anand > > Without patch > / # mount -t vfat /dev/mmcblk0 /mnt/mmc > / # cat /proc/interrupts | grep mmc > 83: 90 INTC mmc0 > 384: 1 twl4030 mmc0 > / # dd if=/dev/zero of=/mnt/mmc/32kbs.txt bs=32k count=1000 > 1000+0 records in > 1000+0 records out > / # cat /proc/interrupts | grep mmc > 83: 3760 INTC mmc0 > 384: 1 twl4030 mmc0 > / # dd if=/dev/zero of=/mnt/mmc/1Mbs.txt bs=1M count=32 > 32+0 records in > 32+0 records out > / # cat /proc/interrupts | grep mmc > 83: 7570 INTC mmc0 > 384: 1 twl4030 mmc0 > / # ls -l /mnt/mmc > -rwxr-xr-x 1 root root 33554432 Dec 31 18:03 1Mbs.txt > -rwxr-xr-x 1 root root 32768000 Dec 31 18:03 32kbs.txt > / # umount /mnt/mmc > > > With patch > / # mount -t vfat /dev/mmcblk0 /mnt/mmc > / # cat /proc/interrupts | grep mmc > 83: 67 INTC mmc0 > 384: 0 twl4030 mmc0 > / # dd if=/dev/zero of=/mnt/mmc/32kbs.txt bs=32k count=1000 > 1000+0 records in > 1000+0 records out > / # cat /proc/interrupts | grep mmc > 83: 3103 INTC mmc0 > 384: 0 twl4030 mmc0 > / # dd if=/dev/zero of=/mnt/mmc/1Mbs.txt bs=1M count=32 > 32+0 records in > 32+0 records out > / # cat /proc/interrupts | grep mmc > 83: 6170 INTC mmc0 > 384: 0 twl4030 mmc0 > / # ls -l /mnt/mmc > -rwxr-xr-x 1 root root 33554432 Dec 31 18:01 1Mbs.txt > -rwxr-xr-x 1 root root 32768000 Dec 31 18:00 32kbs.txt > / # umount /mnt/mmc -- 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
