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drm/i915/pmu: Reconstruct active state on starting busy-stats

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We have a hole in our busy-stat accounting if the pmu is enabled during
a long running batch, the pmu will not start accumulating busy-time
until the next context switch. This then fails tests that are only
sampling a single batch.

v2: Count each active port just once (context in/out events are only on
the first and last assignment to a port).
v3: Avoid hardcoding knowledge of 2 submission ports

Fixes: 30e17b7847 ("drm/i915: Engine busy time tracking")
Testcase: igt/perf_pmu/busy-start
Testcase: igt/perf_pmu/busy-double-start
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180111073031.14614-1-chris@chris-wilson.co.uk
(cherry picked from commit 4900727d35)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This commit is contained in:
Chris Wilson 2018-01-11 07:30:31 +00:00 committed by Rodrigo Vivi
parent 25da77f830
commit cc4f8fc72e
1 changed files with 15 additions and 1 deletions
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16
drivers/gpu/drm/i915/intel_engine_cs.c
View file

@ -1951,8 +1951,22 @@ int intel_enable_engine_stats(struct intel_engine_cs *engine)
spin_lock_irqsave(&engine->stats.lock, flags);
if (engine->stats.enabled == ~0)
goto busy;
if (engine->stats.enabled++ == 0)
if (engine->stats.enabled++ == 0) {
struct intel_engine_execlists *execlists = &engine->execlists;
const struct execlist_port *port = execlists->port;
unsigned int num_ports = execlists_num_ports(execlists);
engine->stats.enabled_at = ktime_get();
/* XXX submission method oblivious? */
while (num_ports-- && port_isset(port)) {
engine->stats.active++;
port++;
}
if (engine->stats.active)
engine->stats.start = engine->stats.enabled_at;
}
spin_unlock_irqrestore(&engine->stats.lock, flags);
return 0;