Messages in this thread | | | Date | Tue, 04 Oct 2005 19:21:37 +0530 | From | Karthik Sarangan <> | Subject | Using DMA in read/write, setting block size for I/O |
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In my application, I have the following code.
int main(void) { char *pcBuffer;
posix_memalign((void **) pcBuffer, 512, 262144); int ifd = open("/dev/sdb", O_DIRECT | O_RDWR); long lLen;
lLen = read(ifd, pcBuffer, 262144); close(ifd); return 0; }
Will the underlying block device read a single 256KB block from the hdd into pcBuffer or will it read 256KB as a set of smaller blocks?
Since the buffer is memory aligned will it enable DMA?
scsi disk driver is adaptec aic79xx.o distro is RedHat Enterprise Linux WS 4 (kernel-2.6.9-11) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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