[igt-dev] [PATCH i-g-t v3 02/11] lib/igt_gt: add intel_measure_ring_size

[Chris Wilson]

Quoting Antonio Argenziano (2018-02-16 00:43:01)
> From: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> 
> The logic to measure the ring size is replicated almost identically in
> several tests. Adding it as a common function will make the code
> cleaner.
> 
> The tests are updated in follow up patches.
> 
> v2:
>         - Move into a new file: 'gem_ring'. (Chris)
> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Signed-off-by: Antonio Argenziano <antonio.argenziano at intel.com>
> 
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  lib/Makefile.sources |   2 +
>  lib/i915/gem_ring.c  | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/i915/gem_ring.h  |  31 ++++++++++++++
>  lib/meson.build      |   2 +
>  4 files changed, 149 insertions(+)
>  create mode 100644 lib/i915/gem_ring.c
>  create mode 100644 lib/i915/gem_ring.h
> 
> diff --git a/lib/Makefile.sources b/lib/Makefile.sources
> index 86fbfeef..5b13ef88 100644
> --- a/lib/Makefile.sources
> +++ b/lib/Makefile.sources
> @@ -9,6 +9,8 @@ lib_source_list =               \
>         i915/gem_scheduler.h    \
>         i915/gem_submission.c   \
>         i915/gem_submission.h   \
> +       i915/gem_ring.h \
> +       i915/gem_ring.c \
>         i915_3d.h               \
>         i915_reg.h              \
>         i915_pciids.h           \
> diff --git a/lib/i915/gem_ring.c b/lib/i915/gem_ring.c
> new file mode 100644
> index 00000000..6da4e638
> --- /dev/null
> +++ b/lib/i915/gem_ring.c
> @@ -0,0 +1,114 @@
> +/*
> + * Copyright �� 2014 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#include "gem_ring.h"
> +
> +#include <signal.h>
> +#include <sys/ioctl.h>
> +
> +#include "intel_reg.h"
> +#include "drmtest.h"
> +#include "ioctl_wrappers.h"
> +#include "igt_dummyload.h"
> +
> +static void alarm_handler(int sig)
> +{
> +}
> +
> +/**
> + * intel_measure_ring_size:
> + * @fd: open i915 drm file descriptor
> + * @engine: execbuf engine flag
> + * @new_ctx: use a new context to account for the space used by the lrc init
> + *
> + * This function calculates the maximum number of batches that can be inserted
> + * at the same time in the ring on the selected engine.
> + *
> + * Returns:
> + * Number of batches that fit in the ring
> + */
> +unsigned int intel_measure_ring_size(int fd, unsigned int engine, bool new_ctx)

Inside gem_ring.c, that would suggest gem_ring_measure() (_inflight?
thinking for a future gem_context_measure_inflight).

s/bool new_ctx/unsigned int flags/ saves adding another bool every time
we want to extend this.

> +       struct sigaction old_sa, sa = { .sa_handler = alarm_handler };
> +       struct drm_i915_gem_exec_object2 obj[2];
> +       struct drm_i915_gem_execbuffer2 execbuf;
> +       const uint32_t bbe = MI_BATCH_BUFFER_END;
> +       unsigned int count, last;
> +       struct itimerval itv;
> +       struct igt_cork_vgem cork;

> +       igt_require_intel(fd);

That should be redundant and just spam by this point. The callers should
have a igt_require_gem() in their initial fixture.

> +
> +       memset(obj, 0, sizeof(obj));
> +       obj[1].handle = gem_create(fd, 4096);
> +       gem_write(fd, obj[1].handle, 0, &bbe, sizeof(bbe));
> +
> +       memset(&execbuf, 0, sizeof(execbuf));
> +       execbuf.buffers_ptr = to_user_pointer(&obj[1]);
> +       execbuf.buffer_count = 1;
> +       execbuf.flags = engine;
> +       gem_execbuf(fd, &execbuf);
> +       gem_sync(fd, obj[1].handle);
> +
> +       obj[0].handle = igt_cork_plug(fd, VGEM_BO, &cork);
> +
> +       execbuf.buffers_ptr = to_user_pointer(obj);
> +       execbuf.buffer_count = 2;
> +
> +       if (new_ctx)
> +               execbuf.rsvd1 = gem_context_create(fd);
> +
> +       sigaction(SIGALRM, &sa, &old_sa);
> +       itv.it_interval.tv_sec = 0;
> +       itv.it_interval.tv_usec = 100;
> +       itv.it_value.tv_sec = 0;
> +       itv.it_value.tv_usec = 1000;
> +       setitimer(ITIMER_REAL, &itv, NULL);
> +
> +       last = -1;
> +       count = 0;
> +       do {
> +               if (ioctl(fd, DRM_IOCTL_I915_GEM_EXECBUFFER2, &execbuf) == 0) {
> +                       count++;
> +                       continue;
> +               }
> +
> +               if (last == count)
> +                       break;
> +
> +               last = count;
> +       } while (1);
> +
> +       memset(&itv, 0, sizeof(itv));
> +       setitimer(ITIMER_REAL, &itv, NULL);
> +       sigaction(SIGALRM, &old_sa, NULL);
> +
> +       igt_cork_unplug(VGEM_BO, &cork);
> +       gem_close(fd, obj[0].handle);
> +       gem_close(fd, obj[1].handle);
> +
> +       if (new_ctx)
> +               gem_context_destroy(fd, execbuf.rsvd1);
> +

gem_quiescent_gpu(fd) to flush the nops before we return.
-Chris