[Mesa-dev] [PATCH 04/70] i965: Share the workaround bo between all contexts
Martin Peres
martin.peres at linux.intel.com
Mon Aug 10 04:26:29 PDT 2015
On 10/08/15 14:25, Martin Peres wrote:
> On 07/08/15 23:13, Chris Wilson wrote:
>> Since the workaround bo is used strictly as a write-only buffer, we need
>> only allocate one per screen and use the same one from all contexts.
>>
>> (The caveat here is during extension initialisation, where we write into
>> and read back register values from the buffer, but that is performed
>> only
>> once for the first context - and baring synchronisation issues should
>> not
>> be a problem. Safer would be to move that also to the screen.)
>>
>> v2: Give the workaround bo its own init function and don't piggy back
>> intel_bufmgr_init() since it is not that related.
>>
>> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> Cc: Kenneth Graunke <kenneth at whitecape.org>
>> Cc: Martin Peres <martin.peres at linux.intel.com>
>> ---
>> src/mesa/drivers/dri/i965/brw_context.c | 7 +------
>> src/mesa/drivers/dri/i965/brw_context.h | 4 ++--
>> src/mesa/drivers/dri/i965/brw_pipe_control.c | 13 ++++---------
>> src/mesa/drivers/dri/i965/intel_screen.c | 15 +++++++++++++++
>> src/mesa/drivers/dri/i965/intel_screen.h | 1 +
>> 5 files changed, 23 insertions(+), 17 deletions(-)
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_context.c
>> b/src/mesa/drivers/dri/i965/brw_context.c
>> index efcd91a..ac744d7 100644
>> --- a/src/mesa/drivers/dri/i965/brw_context.c
>> +++ b/src/mesa/drivers/dri/i965/brw_context.c
>> @@ -819,12 +819,7 @@ brwCreateContext(gl_api api,
>> }
>> }
>> - if (brw_init_pipe_control(brw, devinfo)) {
>> - *dri_ctx_error = __DRI_CTX_ERROR_NO_MEMORY;
>> - intelDestroyContext(driContextPriv);
>> - return false;
>> - }
>> -
>> + brw_init_pipe_control(brw, devinfo);
>> brw_init_state(brw);
>> intelInitExtensions(ctx);
>> diff --git a/src/mesa/drivers/dri/i965/brw_context.h
>> b/src/mesa/drivers/dri/i965/brw_context.h
>> index ffdf821..166b852 100644
>> --- a/src/mesa/drivers/dri/i965/brw_context.h
>> +++ b/src/mesa/drivers/dri/i965/brw_context.h
>> @@ -2016,8 +2016,8 @@ gen9_use_linear_1d_layout(const struct
>> brw_context *brw,
>> const struct intel_mipmap_tree *mt);
>> /* brw_pipe_control.c */
>> -int brw_init_pipe_control(struct brw_context *brw,
>> - const struct brw_device_info *info);
>> +void brw_init_pipe_control(struct brw_context *brw,
>> + const struct brw_device_info *info);
>> void brw_fini_pipe_control(struct brw_context *brw);
>> void brw_emit_pipe_control_flush(struct brw_context *brw,
>> uint32_t flags);
>> diff --git a/src/mesa/drivers/dri/i965/brw_pipe_control.c
>> b/src/mesa/drivers/dri/i965/brw_pipe_control.c
>> index 7ee3cb6..872bfe8 100644
>> --- a/src/mesa/drivers/dri/i965/brw_pipe_control.c
>> +++ b/src/mesa/drivers/dri/i965/brw_pipe_control.c
>> @@ -330,26 +330,21 @@ brw_emit_mi_flush(struct brw_context *brw)
>> brw_render_cache_set_clear(brw);
>> }
>> -int
>> +void
>> brw_init_pipe_control(struct brw_context *brw,
>> const struct brw_device_info *devinfo)
>> {
>> if (devinfo->gen < 6)
>> - return 0;
>> + return;
>> /* We can't just use brw_state_batch to get a chunk of space for
>> * the gen6 workaround because it involves actually writing to
>> * the buffer, and the kernel doesn't let us write to the batch.
>> */
>> - brw->workaround_bo = drm_intel_bo_alloc(brw->bufmgr,
>> - "pipe_control workaround",
>> - 4096, 4096);
>> - if (brw->workaround_bo == NULL)
>> - return -ENOMEM;
>> + brw->workaround_bo = brw->intelScreen->workaround_bo;
>> + drm_intel_bo_reference(brw->workaround_bo);
>
> Why do you need reference counting here? Why not simply destroy the
> buffer when the screen is destroyed? I would assume that a screen
> could not be destroyed until all its associated contexts are gone, right?
>
> In any case, it seems to improve performance by a few percent for
> Synmark OglBatch7.
Forgot to add my R-b:
Reviewed-by: Martin Peres <martin.peres at linux.intel.com>
>
>> brw->pipe_controls_since_last_cs_stall = 0;
>> -
>> - return 0;
>> }
>> void
>> diff --git a/src/mesa/drivers/dri/i965/intel_screen.c
>> b/src/mesa/drivers/dri/i965/intel_screen.c
>> index 147fa1e..61f1dbe 100644
>> --- a/src/mesa/drivers/dri/i965/intel_screen.c
>> +++ b/src/mesa/drivers/dri/i965/intel_screen.c
>> @@ -967,6 +967,7 @@ intelDestroyScreen(__DRIscreen * sPriv)
>> {
>> struct intel_screen *intelScreen = sPriv->driverPrivate;
>> + drm_intel_bo_unreference(intelScreen->workaround_bo);
>> dri_bufmgr_destroy(intelScreen->bufmgr);
>> driDestroyOptionInfo(&intelScreen->optionCache);
>> @@ -1106,6 +1107,17 @@ intel_init_bufmgr(struct intel_screen
>> *intelScreen)
>> }
>> static bool
>> +intel_init_workaround_bo(struct intel_screen *intelScreen)
>> +{
>> + /* A small scratch bo shared by all contexts, primarily used
>> + * for doing PIPECONTROL serialisation writes that are discarded.
>> + */
>> + intelScreen->workaround_bo =
>> + drm_intel_bo_alloc(intelScreen->bufmgr, "pipe_control w/a",
>> 4096, 4096);
>> + return intelScreen->workaround_bo != NULL;
>> +}
>> +
>> +static bool
>> intel_detect_swizzling(struct intel_screen *screen)
>> {
>> drm_intel_bo *buffer;
>> @@ -1417,6 +1429,9 @@ __DRIconfig **intelInitScreen2(__DRIscreen *psp)
>> if (!intel_init_bufmgr(intelScreen))
>> return false;
>> + if (!intel_init_workaround_bo(intelScreen))
>> + return false;
>> +
>> intelScreen->deviceID =
>> drm_intel_bufmgr_gem_get_devid(intelScreen->bufmgr);
>> intelScreen->devinfo = brw_get_device_info(intelScreen->deviceID,
>> brw_get_revision(psp->fd));
>> diff --git a/src/mesa/drivers/dri/i965/intel_screen.h
>> b/src/mesa/drivers/dri/i965/intel_screen.h
>> index 0bae95e..76179fc 100644
>> --- a/src/mesa/drivers/dri/i965/intel_screen.h
>> +++ b/src/mesa/drivers/dri/i965/intel_screen.h
>> @@ -65,6 +65,7 @@ struct intel_screen
>> bool has_context_reset_notification : 1;
>> dri_bufmgr *bufmgr;
>> + drm_intel_bo *workaround_bo;
>> /**
>> * A unique ID for shader programs.
>
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