Il giorno 05/set/2016, alle ore 17:56, Bartlomiej Zolnierkiewicz <b.zolnier...@samsung.com> ha scritto:
> > Hi, > > On Thursday, September 01, 2016 10:39:46 AM Linus Walleij wrote: >> On Thu, Sep 1, 2016 at 12:09 AM, Mark Brown <broo...@kernel.org> wrote: >> >>> - Do some benchmarks on the current status of the various branches on >>> relevant hardware (including trying to convert some of these slower >>> devices to blk-mq and seeing what happens). Linus has been working >>> on this already in the context of MMC. >> >> I'm trying to do a patch switching MMC to use blk-mq, so I can >> benchmark performance before/after this. >> >> While we expect mq to perform worse on single-hardware-queue >> devices like these, we don't know until we tried, so I'm trying. > > I did this (switched MMC to blk-mq) some time ago. Patches are > extremely ugly and hacky (basically the whole MMC block layer > glue code needs to be re-done) so I'm rather reluctant to > sharing them yet (to be honest I would like to rewrite them > completely before posting). > > I only did linear read tests (using dd) so far and results that > I got were mixed (BTW the hardware I'm doing this work on is > Odroid-XU3). Pure block performance under maximum CPU frequency > was slightly worse (5-12%) but the CPU consumption was reduced so > when CPU was scaled down manually (or ondemand CPUfreq governor > was used) blk-mq mode results were better then vanilla ones (up > to 10% when CPU was scaled down to minimum frequency and even > up to 50% when using ondemand governor - this finding is very > interesting and needs to be investigated further). > IMO, another important figure of merit is application- and system-level latency (e.g., application/system responsiveness or frame drop rate with audio/video playback/streaming, while the device happens to be busy with furhter I/O). Scripts to measure it can be found, e.g., here [1] for desktop systems. If I can, I'm willing to help in any respect. Thanks, Paolo [1] https://github.com/Algodev-github/S > Best regards, > -- > Bartlomiej Zolnierkiewicz > Samsung R&D Institute Poland > Samsung Electronics > > -- > To unsubscribe from this list: send the line "unsubscribe linux-block" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
