Robin Humble wrote: > On Thu, Jan 24, 2008 at 02:10:06PM +0300, Vladislav Bolkhovitin wrote: > >>>On Jan 24, 2008 8:06 AM, Robin Humble <[EMAIL PROTECTED]> wrote: >>> >>>>how are write speeds with SCST SRP? >>>>for some kernels and tests tgt writes at >2x the read speed. >> >>There is a fundamental difference between regular dd-like reads and writes: >>reads are sync, i.e. latency sensitive, but writes are async, i.e. latency >>insensitive. You should use O_DIRECT dd writes for the fair comparison. > > I agree, although the vast majority of applications don't use O_DIRECT.
Sorry, it isn't about O_DIRECT usage. It's about latency bound or not workload. > anwyay, the direct i/o results were in the email: > > direct i/o dd > write/read 800/751 MB/s > dd if=/dev/zero of=/dev/sdc bs=1M count=5000 oflag=direct > dd of=/dev/null if=/dev/sdc bs=1M count=5000 iflag=direct > > I couldn't find a direct i/o option for lmdd. > > cheers, > robin > - > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > _______________________________________________ Stgt-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/stgt-devel
