Re: [Intel-gfx] [igt-dev] [PATCH i-g-t] i915/gem_mmap_gtt: Trim object size for ptracing

From: Mika Kuoppala <mika.kuoppala@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>, intel-gfx@lists.freedesktop.org
Cc: igt-dev@lists.freedesktop.org, Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [Intel-gfx] [igt-dev] [PATCH i-g-t] i915/gem_mmap_gtt: Trim object size for ptracing
Date: Fri, 23 Oct 2020 13:21:45 +0300	[thread overview]
Message-ID: <87tuulqm2u.fsf@gaia.fi.intel.com> (raw)
In-Reply-To: <20201022150943.3041180-1-chris@chris-wilson.co.uk>

Chris Wilson <chris@chris-wilson.co.uk> writes:

> For verifying vm_ops.access we only need a page or two to check we both
> advance across a page boundary and find the right offset within a page.
> 16MiB is overkill for the slow uncached reads through the slow ptrace
> interface, so reduce the object size by a couple of orders of magnitude.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

> ---
>  tests/i915/gem_mmap_gtt.c | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/tests/i915/gem_mmap_gtt.c b/tests/i915/gem_mmap_gtt.c
> index 6637bba06..3cce19e9a 100644
> --- a/tests/i915/gem_mmap_gtt.c
> +++ b/tests/i915/gem_mmap_gtt.c
> @@ -525,6 +525,7 @@ static void *memchr_inv(const void *s, int c, size_t n)
>  static void
>  test_ptrace(int fd)
>  {
> +	unsigned long sz = 16 * 4096;
>  	unsigned long AA, CC;
>  	unsigned long *gtt, *cpy;
>  	uint32_t bo;
> @@ -533,16 +534,16 @@ test_ptrace(int fd)
>  	memset(&AA, 0xaa, sizeof(AA));
>  	memset(&CC, 0x55, sizeof(CC));
>  
> -	cpy = malloc(OBJECT_SIZE);
> -	memset(cpy, AA, OBJECT_SIZE);
> +	cpy = malloc(sz);
> +	memset(cpy, AA, sz);
>  
> -	bo = gem_create(fd, OBJECT_SIZE);
> -	gtt = mmap_bo(fd, bo, OBJECT_SIZE);
> -	memset(gtt, CC, OBJECT_SIZE);
> +	bo = gem_create(fd, sz);
> +	gtt = mmap_bo(fd, bo, sz);
> +	memset(gtt, CC, sz);
>  	gem_close(fd, bo);
>  
> -	igt_assert(!memchr_inv(gtt, CC, OBJECT_SIZE));
> -	igt_assert(!memchr_inv(cpy, AA, OBJECT_SIZE));
> +	igt_assert(!memchr_inv(gtt, CC, sz));
> +	igt_assert(!memchr_inv(cpy, AA, sz));
>  
>  	igt_fork(child, 1) {
>  		ptrace(PTRACE_TRACEME, 0, NULL, NULL);
> @@ -553,7 +554,7 @@ test_ptrace(int fd)
>  	pid = wait(NULL);
>  
>  	ptrace(PTRACE_ATTACH, pid, NULL, NULL);
> -	for (int i = 0; i < OBJECT_SIZE / sizeof(long); i++) {
> +	for (int i = 0; i < sz / sizeof(long); i++) {
>  		long ret;
>  
>  		ret = ptrace(PTRACE_PEEKDATA, pid, gtt + i);
> @@ -570,10 +571,10 @@ test_ptrace(int fd)
>  	igt_waitchildren();
>  
>  	/* The contents of the two buffers should now be swapped */
> -	igt_assert(!memchr_inv(gtt, AA, OBJECT_SIZE));
> -	igt_assert(!memchr_inv(cpy, CC, OBJECT_SIZE));
> +	igt_assert(!memchr_inv(gtt, AA, sz));
> +	igt_assert(!memchr_inv(cpy, CC, sz));
>  
> -	munmap(gtt, OBJECT_SIZE);
> +	munmap(gtt, sz);
>  	free(cpy);
>  }
>  
> -- 
> 2.28.0
>
> _______________________________________________
> igt-dev mailing list
> igt-dev@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/igt-dev
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx