On 5/16/2022 00:59, Jani Nikula wrote:
On Sat, 14 May 2022, Vinay Belgaumkarvinay.belgaumkar@intel.com wrote:
SLPC min/max frequency updates require H2G calls. We are seeing timeouts when GuC channel is backed up and it is unable to respond in a timely fashion causing warnings and affecting CI.
This is seen when waitboosting happens during a stress test. this patch updates the waitboost path to use a non-blocking H2G call instead, which returns as soon as the message is successfully transmitted.
v2: Use drm_notice to report any errors that might occur while sending the waitboost H2G request (Tvrtko)
Signed-off-by: Vinay Belgaumkarvinay.belgaumkar@intel.com
drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 44 +++++++++++++++++---- 1 file changed, 36 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c index 1db833da42df..e5e869c96262 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c @@ -98,6 +98,30 @@ static u32 slpc_get_state(struct intel_guc_slpc *slpc) return data->header.global_state; }
+static int guc_action_slpc_set_param_nb(struct intel_guc *guc, u8 id, u32 value) +{
- u32 request[] = {
static const
GUC_ACTION_HOST2GUC_PC_SLPC_REQUEST,SLPC_EVENT(SLPC_EVENT_PARAMETER_SET, 2),id,value,- };
- int ret;
- ret = intel_guc_send_nb(guc, request, ARRAY_SIZE(request), 0);
- return ret > 0 ? -EPROTO : ret;
+}
+static int slpc_set_param_nb(struct intel_guc_slpc *slpc, u8 id, u32 value) +{
- struct intel_guc *guc = slpc_to_guc(slpc);
- GEM_BUG_ON(id >= SLPC_MAX_PARAM);
- return guc_action_slpc_set_param_nb(guc, id, value);
+}
- static int guc_action_slpc_set_param(struct intel_guc *guc, u8 id, u32 value) { u32 request[] = {
Ditto here, and the whole gt/uc directory seems to have tons of these u32 action/request array variables on stack, with the required initialization, that could be in rodata.
Please fix all of them.
BR, Jani.
But the only constant is the action code. Everything else is parameters and will be different on each call.
You mean something like this?
static const u32 template[] = { action, }; u32 *request = kmalloc_array(sizeof(*request), 4); memcpy(request, template, sizeof(*request) * 1); request[1] = param0; request[2] = param1; request[3] = param2; ret = send(request); kfree(request); return ret;
Not seeing how that would be an improvement. It's a lot more code, a lot less readable, more prone to bugs due to incorrect structure sizes and/or params in the wrong place. The current version is easy to read and therefore to maintain, almost impossible to get wrong, and only puts a few words on the stack. I think the largest request is region of 15 words? I'm not seeing what the problem is.
John.
@@ -208,12 +232,10 @@ static int slpc_force_min_freq(struct intel_guc_slpc *slpc, u32 freq) */
with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
ret = slpc_set_param(slpc,SLPC_PARAM_GLOBAL_MIN_GT_UNSLICE_FREQ_MHZ,freq);if (ret)i915_probe_error(i915, "Unable to force min freq to %u: %d",freq, ret);
/* Non-blocking request will avoid stalls */ret = slpc_set_param_nb(slpc,SLPC_PARAM_GLOBAL_MIN_GT_UNSLICE_FREQ_MHZ,freq);}
return ret;
@@ -222,6 +244,8 @@ static int slpc_force_min_freq(struct intel_guc_slpc *slpc, u32 freq) static void slpc_boost_work(struct work_struct *work) { struct intel_guc_slpc *slpc = container_of(work, typeof(*slpc), boost_work);
struct drm_i915_private *i915 = slpc_to_i915(slpc);
int err;
/*
- Raise min freq to boost. It's possible that
@@ -231,8 +255,12 @@ static void slpc_boost_work(struct work_struct *work) */ mutex_lock(&slpc->lock); if (atomic_read(&slpc->num_waiters)) {
slpc_force_min_freq(slpc, slpc->boost_freq);slpc->num_boosts++;
err = slpc_force_min_freq(slpc, slpc->boost_freq);if (!err)slpc->num_boosts++;elsedrm_notice(&i915->drm, "Failed to send waitboost request (%d)\n",err);