From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Frysinger Date: Sat, 11 Aug 2012 13:50:10 -0400 Subject: [U-Boot] [PATCH] mtest: Disable dcache during test In-Reply-To: <1725235724.2300239.1344694624384.JavaMail.root@advansee.com> References: <1725235724.2300239.1344694624384.JavaMail.root@advansee.com> Message-ID: <201208111350.10837.vapier@gentoo.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Saturday 11 August 2012 10:17:04 Beno?t Th?baudeau wrote: > On 08/11/2012 05:18 AM, Mike Frysinger wrote: > > On Friday 10 August 2012 15:16:15 Beno?t Th?baudeau wrote: > > > mtest is supposed to test many types of memory accesses in many > > > different > > > conditions. If dcache is enabled, memory accesses are likely > > > bursts, and > > > some memory accesses are simply skipped. Hence, dcache should be > > > disabled > > > during mtest operation so that what mtest actually tests is not > > > masked by > > > dcache. > > > > if you want dcache disabled, then why don't you run `dcache off` > > first ? i > > think it's useful to be able to do both, and forcing it one way is > > wrong. > > > > thus, NAK from me. > > Because you will very likely trust mtest and forget about running `dcache > off` first, so you may then be happy about falsely positive mtest results. there are a lot of commands in u-boot that people could "easily forget" to tweak and have it do the wrong thing. imo, mtest running in the active cache/memory settings is the *expected* behavior rather than having it silently reconfigure the system behind the back of the user. > Moreover, I can't find any sense or usefulness in running mtest with > dcache enabled. it can be useful to stress test the system with cache enabled. i recall during some early porting work that being able to test both caught bugs that we might have missed otherwise. > If there is really a need for running mtest with dcache enabled, an option > (disabled by default) could be added to the command line to tell mtest not > to disable dcache. we already have such an option: dcache off; mtest; dcache on -mike -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 836 bytes Desc: This is a digitally signed message part. URL: