[i-g-t] tests/dumb_buffer: Try to compute the largest possible dumb buffer
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Message ID 20200123122711.1390696-1-chris@chris-wilson.co.uk
State New
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  • [i-g-t] tests/dumb_buffer: Try to compute the largest possible dumb buffer
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Commit Message

Chris Wilson Jan. 23, 2020, 12:27 p.m. UTC
For our threaded clear test, we want to create as many buffers as can
fit into the available memory. However, since we don't know the size of
that available memory, it can be easy to create too large or too many
buffers, and waste our time testing the unobtainable. Instead, try
probing the available space by trying to create the largest dumb buffer
we possibly can, and assume that is the equivalent to the available
space.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ramalingam C <ramalingam.c@intel.com>
---
 tests/dumb_buffer.c | 68 +++++++++++++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 9 deletions(-)

Comments

Ramalingam C Jan. 27, 2020, 6:41 a.m. UTC | #1
On 2020-01-23 at 12:27:11 +0000, Chris Wilson wrote:
> For our threaded clear test, we want to create as many buffers as can
> fit into the available memory. However, since we don't know the size of
> that available memory, it can be easy to create too large or too many
> buffers, and waste our time testing the unobtainable. Instead, try
> probing the available space by trying to create the largest dumb buffer
> we possibly can, and assume that is the equivalent to the available
> space.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ramalingam C <ramalingam.c@intel.com>
> ---
>  tests/dumb_buffer.c | 68 +++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 59 insertions(+), 9 deletions(-)
> 
> diff --git a/tests/dumb_buffer.c b/tests/dumb_buffer.c
> index 3d2dc9966..c1e7b4d3b 100644
> --- a/tests/dumb_buffer.c
> +++ b/tests/dumb_buffer.c
> @@ -31,18 +31,18 @@
>   * combinations are rejected.
>   */
>  
> -#include <stdlib.h>
> -#include <sys/ioctl.h>
> -#include <stdio.h>
> -#include <string.h>
> +#include <errno.h>
>  #include <fcntl.h>
>  #include <inttypes.h>
> -#include <errno.h>
> -#include <sys/stat.h>
> -#include <sys/time.h>
> -#include <getopt.h>
>  #include <pthread.h>
> +#include <signal.h>
>  #include <stdatomic.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <sys/stat.h>
> +#include <sys/time.h>
>  
>  #include <drm.h>
>  
> @@ -325,12 +325,62 @@ static void *thread_clear(void *data)
>  	return (void *)(uintptr_t)checked;
>  }
>  
> +static jmp_buf sigjmp;
> +
> +static void sigprobe(int sig)
> +{
> +	longjmp(sigjmp, sig);
> +}
> +
> +static uint64_t estimate_largest_dumb_buffer(int fd)
> +{
> +	sighandler_t old_sigbus = signal(SIGBUS, sigprobe);
> +	sighandler_t old_sigsegv = signal(SIGSEGV, sigprobe);
> +	struct drm_mode_create_dumb create = {
> +		.bpp = 32,
> +		.width = 1 << 20, /* in pixels */
> +		.height = 1, /* in rows */
> +	};
> +	volatile uint64_t largest = 0;
> +	char * volatile ptr = NULL;
> +
> +	if (setjmp(sigjmp)) {
> +		if (ptr)
> +			munmap(ptr, create.size);
> +
> +		signal(SIGBUS, old_sigbus);
> +		signal(SIGSEGV, old_sigsegv);
> +
> +		igt_info("Largest dumb buffer sucessfully created: %'"PRIu64" bytes\n",
> +			 largest);
> +		return largest / PAGE_SIZE;
> +	}
> +
> +	for (create.height = 1; create.height; create.height *= 2) {
> +		if (__dumb_create(fd, &create))
> +			longjmp(sigjmp, SIGABRT);
> +
> +		ptr = __dumb_map(fd, create.handle, create.size, PROT_READ);
> +		dumb_destroy(fd, create.handle);
> +		if (!ptr)
> +			longjmp(sigjmp, SIGABRT);
> +
> +		if (!*ptr)
> +			largest = create.size;
> +
> +		munmap(ptr, create.size);
> +		ptr = NULL;
> +	}
> +
> +	longjmp(sigjmp, SIGABRT);
> +}
> +
>  static void always_clear(int fd, int timeout)
>  {
>  	struct thread_clear arg = {
>  		.fd = fd,
>  		.timeout = timeout,
> -		.max = intel_get_avail_ram_mb() << (20 - 12), /* in pages */
> +		.max = estimate_largest_dumb_buffer(fd), /* in pages */
LGTM. I will test with other required LMEM changes.

Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
>  	};
>  	const int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
>  	unsigned long checked;
> -- 
> 2.25.0
>

Patch
diff mbox series

diff --git a/tests/dumb_buffer.c b/tests/dumb_buffer.c
index 3d2dc9966..c1e7b4d3b 100644
--- a/tests/dumb_buffer.c
+++ b/tests/dumb_buffer.c
@@ -31,18 +31,18 @@ 
  * combinations are rejected.
  */
 
-#include <stdlib.h>
-#include <sys/ioctl.h>
-#include <stdio.h>
-#include <string.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
-#include <errno.h>
-#include <sys/stat.h>
-#include <sys/time.h>
-#include <getopt.h>
 #include <pthread.h>
+#include <signal.h>
 #include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/time.h>
 
 #include <drm.h>
 
@@ -325,12 +325,62 @@  static void *thread_clear(void *data)
 	return (void *)(uintptr_t)checked;
 }
 
+static jmp_buf sigjmp;
+
+static void sigprobe(int sig)
+{
+	longjmp(sigjmp, sig);
+}
+
+static uint64_t estimate_largest_dumb_buffer(int fd)
+{
+	sighandler_t old_sigbus = signal(SIGBUS, sigprobe);
+	sighandler_t old_sigsegv = signal(SIGSEGV, sigprobe);
+	struct drm_mode_create_dumb create = {
+		.bpp = 32,
+		.width = 1 << 20, /* in pixels */
+		.height = 1, /* in rows */
+	};
+	volatile uint64_t largest = 0;
+	char * volatile ptr = NULL;
+
+	if (setjmp(sigjmp)) {
+		if (ptr)
+			munmap(ptr, create.size);
+
+		signal(SIGBUS, old_sigbus);
+		signal(SIGSEGV, old_sigsegv);
+
+		igt_info("Largest dumb buffer sucessfully created: %'"PRIu64" bytes\n",
+			 largest);
+		return largest / PAGE_SIZE;
+	}
+
+	for (create.height = 1; create.height; create.height *= 2) {
+		if (__dumb_create(fd, &create))
+			longjmp(sigjmp, SIGABRT);
+
+		ptr = __dumb_map(fd, create.handle, create.size, PROT_READ);
+		dumb_destroy(fd, create.handle);
+		if (!ptr)
+			longjmp(sigjmp, SIGABRT);
+
+		if (!*ptr)
+			largest = create.size;
+
+		munmap(ptr, create.size);
+		ptr = NULL;
+	}
+
+	longjmp(sigjmp, SIGABRT);
+}
+
 static void always_clear(int fd, int timeout)
 {
 	struct thread_clear arg = {
 		.fd = fd,
 		.timeout = timeout,
-		.max = intel_get_avail_ram_mb() << (20 - 12), /* in pages */
+		.max = estimate_largest_dumb_buffer(fd), /* in pages */
 	};
 	const int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
 	unsigned long checked;