GL slowdown with latest kernel

I see a ~3x reduced GL performance as measured by glxgears. This is on a dual 
Athlon sysmem with Radeon 9000 Pro.

Old kernel:
[yuri_at_ice][~]# uname -a
FreeBSD ice.irfu.se 5.1-CURRENT FreeBSD 5.1-CURRENT #3: Wed Oct 22 10:15:08 
CEST 2003     root_at_ice.irfu.se:/usr/src/sys/i386/compile/ICE  i386
[yuri_at_ice][~]# glxgears
7128 frames in 5.0 seconds = 1425.600 FPS
8738 frames in 5.0 seconds = 1747.600 FPS
8689 frames in 5.0 seconds = 1737.800 FPS
8725 frames in 5.0 seconds = 1745.000 FPS
8727 frames in 5.0 seconds = 1745.400 FPS
8717 frames in 5.0 seconds = 1743.400 FPS
8717 frames in 5.0 seconds = 1743.400 FPS
8720 frames in 5.0 seconds = 1744.000 FPS
8711 frames in 5.0 seconds = 1742.200 FPS

New kernel:
[yuri_at_ice][~]# uname -a
FreeBSD ice.irfu.se 5.1-CURRENT FreeBSD 5.1-CURRENT #6: Tue Oct 28 09:06:24 
CET 2003     root_at_ice.irfu.se:/usr/src/sys/i386/compile/ICE  i386

[yuri_at_ice][~]# glxgears
2851 frames in 5.0 seconds = 570.200 FPS
2961 frames in 5.0 seconds = 592.200 FPS
2873 frames in 5.0 seconds = 574.600 FPS
2866 frames in 5.0 seconds = 573.200 FPS
2877 frames in 5.0 seconds = 575.400 FPS
2863 frames in 5.0 seconds = 572.600 FPS
2884 frames in 5.0 seconds = 576.800 FPS
3436 frames in 5.0 seconds = 687.200 FPS
X connection to :0.0 broken (explicit kill or server shutdown).
[yuri_at_ice][~]# glxinfo
name of display: :0.0
display: :0  screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.2
server glx extensions:
    GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_EXT_import_context,
    GLX_SGI_make_current_read
client glx vendor string: SGI
client glx version string: 1.2
client glx extensions:
    GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context,
    GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_allocate_memory,
    GLX_MESA_swap_control, GLX_MESA_swap_frame_usage, GLX_OML_swap_method,
    GLX_OML_sync_control, GLX_SGI_make_current_read, GLX_SGI_swap_control,
    GLX_SGI_video_sync, GLX_SGIS_multisample, GLX_SGIX_fbconfig,
    GLX_SGIX_visual_select_group
GLX extensions:
    GLX_ARB_get_proc_address, GLX_EXT_import_context, GLX_EXT_visual_info,
    GLX_EXT_visual_rating, GLX_MESA_allocate_memory, GLX_MESA_swap_control,
    GLX_MESA_swap_frame_usage, GLX_SGI_video_sync
OpenGL vendor string: Tungsten Graphics, Inc.
OpenGL renderer string: Mesa DRI R200 20030328 AGP 1x x86/MMX+/3DNow!+/SSE TCL
OpenGL version string: 1.3 Mesa 5.0.2
OpenGL extensions:
    GL_ARB_imaging, GL_ARB_multisample, GL_ARB_multitexture,
    GL_ARB_texture_border_clamp, GL_ARB_texture_compression,
    GL_ARB_texture_cube_map, GL_ARB_texture_env_add,
    GL_ARB_texture_env_combine, GL_ARB_texture_env_dot3,
    GL_ARB_texture_mirrored_repeat, GL_ARB_transpose_matrix,
    GL_ARB_window_pos, GL_EXT_abgr, GL_EXT_bgra, GL_EXT_blend_color,
    GL_EXT_blend_logic_op, GL_EXT_blend_minmax, GL_EXT_blend_subtract,
    GL_EXT_clip_volume_hint, GL_EXT_compiled_vertex_array, GL_EXT_convolution,
    GL_EXT_copy_texture, GL_EXT_draw_range_elements, GL_EXT_histogram,
    GL_EXT_packed_pixels, GL_EXT_polygon_offset, GL_EXT_rescale_normal,
    GL_EXT_secondary_color, GL_EXT_separate_specular_color,
    GL_EXT_stencil_wrap, GL_EXT_subtexture, GL_EXT_texture, GL_EXT_texture3D,
    GL_EXT_texture_edge_clamp, GL_EXT_texture_env_add,
    GL_EXT_texture_env_combine, GL_EXT_texture_env_dot3,
    GL_EXT_texture_filter_anisotropic, GL_EXT_texture_object,
    GL_EXT_texture_lod_bias, GL_EXT_vertex_array, GL_APPLE_packed_pixels,
    GL_ATI_texture_env_combine3, GL_ATI_texture_mirror_once,
    GL_IBM_rasterpos_clip, GL_IBM_texture_mirrored_repeat,
    GL_MESA_pack_invert, GL_MESA_ycbcr_texture, GL_MESA_window_pos,
    GL_NV_blend_square, GL_NV_texture_rectangle, GL_NV_texgen_reflection,
    GL_SGI_color_matrix, GL_SGI_color_table, GL_SGIS_generate_mipmap,
    GL_SGIS_texture_border_clamp, GL_SGIS_texture_edge_clamp,
    GL_SGIS_texture_lod
glu version: 1.3
glu extensions:
    GLU_EXT_nurbs_tessellator, GLU_EXT_object_space_tess

   visual  x  bf lv rg d st colorbuffer ax dp st accumbuffer  ms  cav
 id dep cl sp sz l  ci b ro  r  g  b  a bf th cl  r  g  b  a ns b eat
----------------------------------------------------------------------
0x23 24 tc  0 32  0 r  .  .  8  8  8  8  0 24  0  0  0  0  0  0 0 None
0x24 24 tc  0 32  0 r  .  .  8  8  8  8  0 24  8  0  0  0  0  0 0 None
0x25 24 tc  0 32  0 r  .  .  8  8  8  8  0 24  0 16 16 16 16  0 0 Slow
0x26 24 tc  0 32  0 r  .  .  8  8  8  8  0 24  8 16 16 16 16  0 0 Slow
0x27 24 tc  0 32  0 r  y  .  8  8  8  8  0 24  0  0  0  0  0  0 0 None
0x28 24 tc  0 32  0 r  y  .  8  8  8  8  0 24  8  0  0  0  0  0 0 None
0x29 24 tc  0 32  0 r  y  .  8  8  8  8  0 24  0 16 16 16 16  0 0 Slow
0x2a 24 tc  0 32  0 r  y  .  8  8  8  8  0 24  8 16 16 16 16  0 0 Slow
0x2b 24 dc  0 32  0 r  .  .  8  8  8  8  0 24  0  0  0  0  0  0 0 None
0x2c 24 dc  0 32  0 r  .  .  8  8  8  8  0 24  8  0  0  0  0  0 0 None
0x2d 24 dc  0 32  0 r  .  .  8  8  8  8  0 24  0 16 16 16 16  0 0 Slow
0x2e 24 dc  0 32  0 r  .  .  8  8  8  8  0 24  8 16 16 16 16  0 0 Slow
0x2f 24 dc  0 32  0 r  y  .  8  8  8  8  0 24  0  0  0  0  0  0 0 None
0x30 24 dc  0 32  0 r  y  .  8  8  8  8  0 24  8  0  0  0  0  0 0 None
0x31 24 dc  0 32  0 r  y  .  8  8  8  8  0 24  0 16 16 16 16  0 0 Slow
0x32 24 dc  0 32  0 r  y  .  8  8  8  8  0 24  8 16 16 16 16  0 0 Slow

Yuri