[02/24] selftests/resctrl: Refactor fill_buf functions

Message ID 20231024092634.7122-3-ilpo.jarvinen@linux.intel.com
State New
Headers
Series selftests/resctrl: CAT test improvements & generalized test framework |

Commit Message

Ilpo Järvinen Oct. 24, 2023, 9:26 a.m. UTC
  There are unnecessary nested calls in fill_buf.c:
  - run_fill_buf() calls fill_cache()
  - alloc_buffer() calls malloc_and_init_memory()

Simplify the code flow and remove those unnecessary call levels by
moving the called code inside the calling function.

Resolve the difference in run_fill_buf() and fill_cache() parameter
name into 'buf_size' which is more descriptive than 'span'.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 tools/testing/selftests/resctrl/fill_buf.c | 58 +++++++---------------
 tools/testing/selftests/resctrl/resctrl.h  |  2 +-
 2 files changed, 20 insertions(+), 40 deletions(-)
  

Comments

Maciej Wieczor-Retman Oct. 27, 2023, 11:32 a.m. UTC | #1
On 2023-10-24 at 12:26:12 +0300, Ilpo Järvinen wrote:
>There are unnecessary nested calls in fill_buf.c:
>  - run_fill_buf() calls fill_cache()
>  - alloc_buffer() calls malloc_and_init_memory()
>
>Simplify the code flow and remove those unnecessary call levels by
>moving the called code inside the calling function.
>
>Resolve the difference in run_fill_buf() and fill_cache() parameter
>name into 'buf_size' which is more descriptive than 'span'.
>
>Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
>---
> tools/testing/selftests/resctrl/fill_buf.c | 58 +++++++---------------
> tools/testing/selftests/resctrl/resctrl.h  |  2 +-
> 2 files changed, 20 insertions(+), 40 deletions(-)
>
>diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
>index f9893edda869..9d0b0bf4b85a 100644
>--- a/tools/testing/selftests/resctrl/fill_buf.c
>+++ b/tools/testing/selftests/resctrl/fill_buf.c
>@@ -51,29 +51,6 @@ static void mem_flush(unsigned char *buf, size_t buf_size)
> 	sb();
> }
> 
>-static void *malloc_and_init_memory(size_t buf_size)
>-{
>-	void *p = NULL;
>-	uint64_t *p64;
>-	size_t s64;
>-	int ret;
>-
>-	ret = posix_memalign(&p, PAGE_SIZE, buf_size);
>-	if (ret < 0)
>-		return NULL;
>-
>-	p64 = (uint64_t *)p;
>-	s64 = buf_size / sizeof(uint64_t);
>-
>-	while (s64 > 0) {
>-		*p64 = (uint64_t)rand();
>-		p64 += (CL_SIZE / sizeof(uint64_t));
>-		s64 -= (CL_SIZE / sizeof(uint64_t));
>-	}
>-
>-	return p;
>-}
>-
> static int fill_one_span_read(unsigned char *buf, size_t buf_size)
> {
> 	unsigned char *end_ptr = buf + buf_size;
>@@ -137,20 +114,33 @@ static int fill_cache_write(unsigned char *buf, size_t buf_size, bool once)
> 
> static unsigned char *alloc_buffer(size_t buf_size, int memflush)
> {
>-	unsigned char *buf;
>+	void *p = NULL;

Is this initialization doing anything? "p" seems to be either overwritten or in
case of an error never accessed.

>+	uint64_t *p64;
>+	size_t s64;
>+	int ret;
> 
>-	buf = malloc_and_init_memory(buf_size);
>-	if (!buf)
>+	ret = posix_memalign(&p, PAGE_SIZE, buf_size);
>+	if (ret < 0)
> 		return NULL;
> 
>+	/* Initialize the buffer */
>+	p64 = (uint64_t *)p;
>+	s64 = buf_size / sizeof(uint64_t);
>+
>+	while (s64 > 0) {
>+		*p64 = (uint64_t)rand();
>+		p64 += (CL_SIZE / sizeof(uint64_t));
>+		s64 -= (CL_SIZE / sizeof(uint64_t));
>+	}
>+
> 	/* Flush the memory before using to avoid "cache hot pages" effect */
> 	if (memflush)
>-		mem_flush(buf, buf_size);
>+		mem_flush(p, buf_size);

Wouldn't renaming "p" to "buf" keep this relationship with "buf_size" more
explicit?

Or is naming void pointers "buffers" not appropriate?

> 
>-	return buf;
>+	return p;
> }
  
Ilpo Järvinen Oct. 27, 2023, 11:41 a.m. UTC | #2
On Fri, 27 Oct 2023, Maciej Wieczór-Retman wrote:

> On 2023-10-24 at 12:26:12 +0300, Ilpo Järvinen wrote:
> >There are unnecessary nested calls in fill_buf.c:
> >  - run_fill_buf() calls fill_cache()
> >  - alloc_buffer() calls malloc_and_init_memory()
> >
> >Simplify the code flow and remove those unnecessary call levels by
> >moving the called code inside the calling function.
> >
> >Resolve the difference in run_fill_buf() and fill_cache() parameter
> >name into 'buf_size' which is more descriptive than 'span'.
> >
> >Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> >---
> > tools/testing/selftests/resctrl/fill_buf.c | 58 +++++++---------------
> > tools/testing/selftests/resctrl/resctrl.h  |  2 +-
> > 2 files changed, 20 insertions(+), 40 deletions(-)
> >
> >diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
> >index f9893edda869..9d0b0bf4b85a 100644
> >--- a/tools/testing/selftests/resctrl/fill_buf.c
> >+++ b/tools/testing/selftests/resctrl/fill_buf.c
> >@@ -51,29 +51,6 @@ static void mem_flush(unsigned char *buf, size_t buf_size)
> > 	sb();
> > }
> > 
> >-static void *malloc_and_init_memory(size_t buf_size)
> >-{
> >-	void *p = NULL;
> >-	uint64_t *p64;
> >-	size_t s64;
> >-	int ret;
> >-
> >-	ret = posix_memalign(&p, PAGE_SIZE, buf_size);
> >-	if (ret < 0)
> >-		return NULL;
> >-
> >-	p64 = (uint64_t *)p;
> >-	s64 = buf_size / sizeof(uint64_t);
> >-
> >-	while (s64 > 0) {
> >-		*p64 = (uint64_t)rand();
> >-		p64 += (CL_SIZE / sizeof(uint64_t));
> >-		s64 -= (CL_SIZE / sizeof(uint64_t));
> >-	}
> >-
> >-	return p;
> >-}
> >-
> > static int fill_one_span_read(unsigned char *buf, size_t buf_size)
> > {
> > 	unsigned char *end_ptr = buf + buf_size;
> >@@ -137,20 +114,33 @@ static int fill_cache_write(unsigned char *buf, size_t buf_size, bool once)
> > 
> > static unsigned char *alloc_buffer(size_t buf_size, int memflush)
> > {
> >-	unsigned char *buf;
> >+	void *p = NULL;
> 
> Is this initialization doing anything? "p" seems to be either overwritten or in
> case of an error never accessed.

I'm aware of that but the compiler is too stupid to know that p is 
initialized if there's no error and spits out a warning so I'll have to 
keep the unnecessary initialization.

> >+	uint64_t *p64;
> >+	size_t s64;
> >+	int ret;
> > 
> >-	buf = malloc_and_init_memory(buf_size);
> >-	if (!buf)
> >+	ret = posix_memalign(&p, PAGE_SIZE, buf_size);
> >+	if (ret < 0)
> > 		return NULL;
> > 
> >+	/* Initialize the buffer */
> >+	p64 = (uint64_t *)p;
> >+	s64 = buf_size / sizeof(uint64_t);
> >+
> >+	while (s64 > 0) {
> >+		*p64 = (uint64_t)rand();
> >+		p64 += (CL_SIZE / sizeof(uint64_t));
> >+		s64 -= (CL_SIZE / sizeof(uint64_t));
> >+	}
> >+
> > 	/* Flush the memory before using to avoid "cache hot pages" effect */
> > 	if (memflush)
> >-		mem_flush(buf, buf_size);
> >+		mem_flush(p, buf_size);
> 
> Wouldn't renaming "p" to "buf" keep this relationship with "buf_size" more
> explicit?

I'll change it to buf. This patch has a long history which preceeds the 
change where I made the buffer ptr naming more consistent and I didn't 
realize I departed here again from the consistent naming until you now 
pointed it out.
  

Patch

diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
index f9893edda869..9d0b0bf4b85a 100644
--- a/tools/testing/selftests/resctrl/fill_buf.c
+++ b/tools/testing/selftests/resctrl/fill_buf.c
@@ -51,29 +51,6 @@  static void mem_flush(unsigned char *buf, size_t buf_size)
 	sb();
 }
 
-static void *malloc_and_init_memory(size_t buf_size)
-{
-	void *p = NULL;
-	uint64_t *p64;
-	size_t s64;
-	int ret;
-
-	ret = posix_memalign(&p, PAGE_SIZE, buf_size);
-	if (ret < 0)
-		return NULL;
-
-	p64 = (uint64_t *)p;
-	s64 = buf_size / sizeof(uint64_t);
-
-	while (s64 > 0) {
-		*p64 = (uint64_t)rand();
-		p64 += (CL_SIZE / sizeof(uint64_t));
-		s64 -= (CL_SIZE / sizeof(uint64_t));
-	}
-
-	return p;
-}
-
 static int fill_one_span_read(unsigned char *buf, size_t buf_size)
 {
 	unsigned char *end_ptr = buf + buf_size;
@@ -137,20 +114,33 @@  static int fill_cache_write(unsigned char *buf, size_t buf_size, bool once)
 
 static unsigned char *alloc_buffer(size_t buf_size, int memflush)
 {
-	unsigned char *buf;
+	void *p = NULL;
+	uint64_t *p64;
+	size_t s64;
+	int ret;
 
-	buf = malloc_and_init_memory(buf_size);
-	if (!buf)
+	ret = posix_memalign(&p, PAGE_SIZE, buf_size);
+	if (ret < 0)
 		return NULL;
 
+	/* Initialize the buffer */
+	p64 = (uint64_t *)p;
+	s64 = buf_size / sizeof(uint64_t);
+
+	while (s64 > 0) {
+		*p64 = (uint64_t)rand();
+		p64 += (CL_SIZE / sizeof(uint64_t));
+		s64 -= (CL_SIZE / sizeof(uint64_t));
+	}
+
 	/* Flush the memory before using to avoid "cache hot pages" effect */
 	if (memflush)
-		mem_flush(buf, buf_size);
+		mem_flush(p, buf_size);
 
-	return buf;
+	return p;
 }
 
-static int fill_cache(size_t buf_size, int memflush, int op, bool once)
+int run_fill_buf(size_t buf_size, int memflush, int op, bool once)
 {
 	unsigned char *buf;
 	int ret;
@@ -164,16 +154,6 @@  static int fill_cache(size_t buf_size, int memflush, int op, bool once)
 	else
 		ret = fill_cache_write(buf, buf_size, once);
 	free(buf);
-
-	return ret;
-}
-
-int run_fill_buf(size_t span, int memflush, int op, bool once)
-{
-	size_t cache_size = span;
-	int ret;
-
-	ret = fill_cache(cache_size, memflush, op, once);
 	if (ret) {
 		printf("\n Error in fill cache\n");
 		return -1;
diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
index a33f414f6019..08b95b5a4949 100644
--- a/tools/testing/selftests/resctrl/resctrl.h
+++ b/tools/testing/selftests/resctrl/resctrl.h
@@ -92,7 +92,7 @@  int write_bm_pid_to_resctrl(pid_t bm_pid, char *ctrlgrp, char *mongrp,
 			    char *resctrl_val);
 int perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu,
 		    int group_fd, unsigned long flags);
-int run_fill_buf(size_t span, int memflush, int op, bool once);
+int run_fill_buf(size_t buf_size, int memflush, int op, bool once);
 int resctrl_val(const char * const *benchmark_cmd, struct resctrl_val_param *param);
 int mbm_bw_change(int cpu_no, const char * const *benchmark_cmd);
 void tests_cleanup(void);