> -----Original Message----- > From: Pierre Ossman [mailto:pierre@xxxxxxxxx] > Sent: Wednesday, September 02, 2009 12:41 PM > To: Madhusudhan > Cc: linux-mmc@xxxxxxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; hch@xxxxxx > Subject: Re: mmcqd cpu utilization > > On Wed, 2 Sep 2009 12:23:59 -0500 > "Madhusudhan" <madhu.cr@xxxxxx> wrote: > > > Hi, > > > > Has anyone monitored the cpu utilization percentage when a MMC/SD card > is in > > use? I have noticed that mmc_queue_thread "mmcqd" consumes a lot of cpu > > cycles in a periodic fashion. What I mean here is that I see spikes of > high > > cpu utilization due to mmcqd. There will a cp or similar which will be > > already consuming cpu to transfer data to the MMC/SD device. Further > mmcqd > > increases that load randomly to a high number. > > > > Has anyone seen similar behavior? Any thoughts? > > > > My guess would be that the omap driver doesn't (cannot?) use the > hardware to wait for busy to end, so the system must poll. > So your guess hints probably at "wait_for_completion(&complete)". Am I correct? Regards, Madhu > Anything better than that guess will require some profiling. :) > > Rgds > -- > -- Pierre Ossman > > WARNING: This correspondence is being monitored by the > Swedish government. Make sure your server uses encryption > for SMTP traffic and consider using PGP for end-to-end > encryption. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
