From mboxrd@z Thu Jan 1 00:00:00 1970 From: rdunlap@xenotime.net (Randy Dunlap) Date: Tue, 5 Jul 2011 16:27:05 -0700 Subject: [PATCH v4] mmc: documentation of mmc non-blocking request usage and design. In-Reply-To: <1309901732-3735-1-git-send-email-per.forlin@linaro.org> References: <1309901732-3735-1-git-send-email-per.forlin@linaro.org> Message-ID: <20110705162705.c3081299.rdunlap@xenotime.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 5 Jul 2011 23:35:32 +0200 Per Forlin wrote: > +MMC block driver > +================ > + > +The issue_rw_rq() in the MMC block driver is made non-blocking. > +The increase in throughput is proportional to the time it takes to > +prepare (major part of preparations are dma_map_sg and dma_unmap_sg) > +a request and how fast the memory is. The faster the MMC/SD is > +the more significant the prepare request time becomes. Roughly the expected > +performance gain is 5% for large writes and 10% on large reads on a L2 cache > +platform. In power save mode, when clocks run on a lower frequency, the DMA > +preparation may cost even more. As long as these slower preparations are run > +in parallel with the transfer performance wont be affected. won't Acked-by: Randy Dunlap thanks. --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***