Date: Thu, 14 Jun 2012 09:29:40 +0200 From: Luca Pizzamiglio <l.pizzamiglio@bally-wulff.de> To: Konstantin Belousov <kostikbel@gmail.com> Cc: x11@freebsd.org Subject: Re: Intel KMS: a memory problem Message-ID: <4FD992E4.9080902@bally-wulff.de> In-Reply-To: <20120613112601.GS2337@deviant.kiev.zoral.com.ua> References: <4FD86E13.6090202@bally-wulff.de> <20120613112601.GS2337@deviant.kiev.zoral.com.ua>
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On 06/13/12 13:26, Konstantin Belousov wrote: > On Wed, Jun 13, 2012 at 12:40:19PM +0200, Luca Pizzamiglio wrote: >> Hi people, >> >> I'm using 9-RELENG with KMS and the last port updated on a SandyBridge >> platform (Intel Graphics) >> With a quite simple openGL application, a panic occurred: >> >> panic: pmap_mapdev: Couldn't alloc kernel virtual memory >> Tracing pid 944 tid 100105 td 0xca85c8a0 >> kdb_enter(c0ffe535,c0ffe535,c103dcff,efa62ac0,1,...) at kdb_enter+0x3a >> panic(c103dcff,5000,c9879151,0,c1a02000,...) at panic+0x18c >> pmap_mapdev_attr(c1a02000,4800,1,1,c911d980,...) at pmap_mapdev_attr+0x7e >> i915_gem_obj_io(2d014008,0,4800,0,0,...) at i915_gem_obj_io+0x513 >> i915_gem_pwrite_ioctl(c9925800,ca827120,ca871300,c0a78b5b,efa62bd4,...) >> at i915_gem_pwrite_ioctl+0x4b >> drm_ioctl(c97e0400,8020645d,ca827120,3,ca85c8a0,...) at drm_ioctl+0x2d8 >> devfs_ioctl_f(c91cb850,8020645d,ca827120,c91b5e80,ca85c8a0,...) at >> devfs_ioctl_f+0x10a >> kern_ioctl(ca85c8a0,4,8020645d,ca827120,a62ccc,...) at kern_ioctl+0x2a0 >> sys_ioctl(ca85c8a0,efa62ccc,c67c4c80,293d3b4e,1,...) at sys_ioctl+0x134 >> syscall(efa62d08) at syscall+0x34a >> Xint0x80_syscall() at Xint0x80_syscall+0x21 >> --- syscall (54, FreeBSD ELF32, sys_ioctl), eip = 0x293d5b93, esp = >> 0xbfbf7f4c, ebp = 0xbfbf7f68 --- >> >> I tried to increase vm.kmem_size and vm.kmem_size_max to 512M, but the >> problem persists. >> >> Any easy idea or workaround? >> In the meanwhile, I'll try to investigate this problem deeper. > > You are probably first who run 32bit kernel on SandyBridge + GEMified > i915 driver. > > From the trace you provided it seems that kernel was unable to find > a free area in KVA for 5 consequtive pages. I would think that you have > relatively high fragmentation of KVA. What load on machine is ? > > Actually, quite some time ago, i915_gem_gtt_write() did mapped gtt > page by page, instead of mapping the whole range of pages undergoing i/o. > I was pointed out that this was major performance bootleneck for GTT > mapped objects. It might be reasonable to restore the slow mode for > 32bit kernels, since people running such kernels on SandyBridge definitely > do not care about performance. > Hi Konstantin, Thanks for the quick reply! yes, maybe I'm the first using 32bit architecture on SandyBridge, but for some internal conflicts (human ones) I should use 32 bit version and performance is an important topic. It's quite strange what are you saying about KVA fragmentation, the load of the machine is really low < 0.3; test scenario is: boot, starting X with twm and launching our openGL application.. after a couple of minutes, it panics. The openGL application draw a black screen and some lines to show performance indexes, like CPU percentage usage, time per frame, and so on. CPU percentage is about 7-9%. The system has 4 GB of memory, but only 3GB are addressable. Any idea how could I monitor memory fragmentation? I would like to try PAE extension to address more memory or use 64 bit world with the 32 bit compatibility layer. PAE extension is easy to test, but for 64bit I need to delete&reinstall&recompile everything... Thanks in advance for the help Best regards, Luca
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