From mboxrd@z Thu Jan 1 00:00:00 1970 From: pavel@ucw.cz (Pavel Machek) Date: Wed, 4 Jul 2018 22:12:18 +0200 Subject: v4.18-rc1 on droid 4: very bad CPU performance In-Reply-To: <20180628090655.GL112168@atomide.com> References: <20180621121542.GA4836@amd> <20180622072005.GF112168@atomide.com> <20180622074936.GG112168@atomide.com> <20180627205834.GB29478@amd> <20180628090655.GL112168@atomide.com> Message-ID: <20180704201218.GC13932@amd> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi! > > I was about to add "facepalm" emoji here, as disabling l2 cache is > > major mistake. OTOH if you also see 20 seconds, then either there is > > another problem, or you need to enable l2 cache, too (and I don't have > > to feel too bad for misconfiguring it). > > OK. I checked and duovero runs only at 600MHz. I can only > get down to 19 seconds with omap2plus_defconfig if I disable > CONFIG_CPU_FREQ so the max speed is maintained from bootloader. > Otherwise it runs at most at 1GHz, I think any higher speeds > need smartreflex and voltage scaling working which we don't > have in the mainline kernel. Not sure what happens with higher > speeds with mainline kernel or if they are unsafe in the long > run. > > Anyways, care to post your .config somewhere so I can see what > the numbers are for me with it? I'm attaching config I'm using for v4.18. In current boot, bzip2 takes 16 seconds. user at devuan:~$ time cat /dev/urandom | head -c 10000000 | sudo nice -n -19 bzip2 -9 - | wc -c 10044705 15.68user 0.53system 15.93 (0m15.931s) elapsed 101.82%CPU I guess I should go back to v4.17 to get 12 seconds..?! Confused, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -------------- next part -------------- A non-text attachment was scrubbed... Name: config.gz Type: application/gzip Size: 29025 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: Digital signature URL: