From: Andrii Nakryiko <andriin@xxxxxx>
Switch strings container to using struct btf and its
btf__add_str()/btf__find_str() APIs, which do equivalent internal string
deduplication. This turns out to be a very significantly faster than using
tsearch functions. To satisfy CTF encoding use case, some hacky string size
fetching approach is utilized, as libbpf doesn't provide direct API to get
total string section size and to copy over just strings data section.
BEFORE:
22,624.28 msec task-clock # 1.000 CPUs utilized
85 context-switches # 0.004 K/sec
3 cpu-migrations # 0.000 K/sec
622,545 page-faults # 0.028 M/sec
68,177,206,387 cycles # 3.013 GHz (24.99%)
114,370,031,619 instructions # 1.68 insn per cycle (25.01%)
26,125,001,179 branches # 1154.733 M/sec (25.01%)
458,861,243 branch-misses # 1.76% of all branches (25.00%)
24,533,455,967 L1-dcache-loads # 1084.386 M/sec (25.02%)
973,500,214 L1-dcache-load-misses # 3.97% of all L1-dcache hits (25.05%)
338,773,561 LLC-loads # 14.974 M/sec (25.02%)
12,651,196 LLC-load-misses # 3.73% of all LL-cache hits (25.00%)
22.628910615 seconds time elapsed
21.341063000 seconds user
1.283763000 seconds sys
AFTER:
18,362.97 msec task-clock # 1.000 CPUs utilized
37 context-switches # 0.002 K/sec
0 cpu-migrations # 0.000 K/sec
626,281 page-faults # 0.034 M/sec
52,480,619,000 cycles # 2.858 GHz (25.00%)
104,736,434,384 instructions # 2.00 insn per cycle (25.01%)
23,878,428,465 branches # 1300.358 M/sec (25.01%)
252,669,685 branch-misses # 1.06% of all branches (25.03%)
21,829,390,952 L1-dcache-loads # 1188.772 M/sec (25.04%)
638,086,339 L1-dcache-load-misses # 2.92% of all L1-dcache hits (25.02%)
212,327,435 LLC-loads # 11.563 M/sec (25.00%)
14,578,117 LLC-load-misses # 6.87% of all LL-cache hits (25.00%)
18.364427347 seconds time elapsed
16.985494000 seconds user
1.377959000 seconds sys
Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
---
ctf_encoder.c | 2 +-
libctf.c | 14 ++++----
libctf.h | 4 +--
strings.c | 91 +++++++++++++++++++--------------------------------
strings.h | 32 +++---------------
5 files changed, 49 insertions(+), 94 deletions(-)
diff --git a/ctf_encoder.c b/ctf_encoder.c
index 3cb455a33098..b761287d4534 100644
--- a/ctf_encoder.c
+++ b/ctf_encoder.c
@@ -248,7 +248,7 @@ int cu__encode_ctf(struct cu *cu, int verbose)
if (cu__cache_symtab(cu) < 0)
goto out_delete;
- ctf__set_strings(ctf, &strings->gb);
+ ctf__set_strings(ctf, strings);
uint32_t id;
struct tag *pos;
diff --git a/libctf.c b/libctf.c
index b7d237fbbd3c..95cbf1ff091e 100644
--- a/libctf.c
+++ b/libctf.c
@@ -19,6 +19,7 @@
#include "ctf.h"
#include "dutil.h"
#include "gobuffer.h"
+#include "strings.h"
bool ctf__ignore_symtab_function(const GElf_Sym *sym, const char *sym_name)
{
@@ -287,7 +288,7 @@ int ctf__load_symtab(struct ctf *ctf)
return ctf->symtab == NULL ? -1 : 0;
}
-void ctf__set_strings(struct ctf *ctf, struct gobuffer *strings)
+void ctf__set_strings(struct ctf *ctf, struct strings *strings)
{
ctf->strings = strings;
}
@@ -570,7 +571,7 @@ int ctf__encode(struct ctf *ctf, uint8_t flags)
size = (gobuffer__size(&ctf->types) +
gobuffer__size(&ctf->objects) +
gobuffer__size(&ctf->funcs) +
- gobuffer__size(ctf->strings));
+ strings__size(ctf->strings));
ctf->size = sizeof(*hdr) + size;
ctf->buf = malloc(ctf->size);
@@ -594,13 +595,13 @@ int ctf__encode(struct ctf *ctf, uint8_t flags)
hdr->ctf_type_off = offset;
offset += gobuffer__size(&ctf->types);
hdr->ctf_str_off = offset;
- hdr->ctf_str_len = gobuffer__size(ctf->strings);
+ hdr->ctf_str_len = strings__size(ctf->strings);
void *payload = ctf->buf + sizeof(*hdr);
gobuffer__copy(&ctf->objects, payload + hdr->ctf_object_off);
gobuffer__copy(&ctf->funcs, payload + hdr->ctf_func_off);
gobuffer__copy(&ctf->types, payload + hdr->ctf_type_off);
- gobuffer__copy(ctf->strings, payload + hdr->ctf_str_off);
+ strings__copy(ctf->strings, payload + hdr->ctf_str_off);
*(char *)(ctf->buf + sizeof(*hdr) + hdr->ctf_str_off) = '\0';
if (flags & CTF_FLAGS_COMPR) {
@@ -623,11 +624,10 @@ int ctf__encode(struct ctf *ctf, uint8_t flags)
}
#if 0
printf("\n\ntypes:\n entries: %d\n size: %u"
- "\nstrings:\n entries: %u\n size: %u\ncompressed size: %d\n",
+ "\nstrings:\n size: %u\ncompressed size: %d\n",
ctf->type_index,
gobuffer__size(&ctf->types),
- gobuffer__nr_entries(ctf->strings),
- gobuffer__size(ctf->strings), size);
+ strings__size(ctf->strings), size);
#endif
int fd = open(ctf->filename, O_RDWR);
if (fd < 0) {
diff --git a/libctf.h b/libctf.h
index 071616c72de3..749be8955c52 100644
--- a/libctf.h
+++ b/libctf.h
@@ -24,7 +24,7 @@ struct ctf {
struct gobuffer objects; /* data/variables */
struct gobuffer types;
struct gobuffer funcs;
- struct gobuffer *strings;
+ struct strings *strings;
char *filename;
size_t size;
int swapped;
@@ -76,7 +76,7 @@ int ctf__add_function(struct ctf *ctf, uint16_t type, uint16_t nr_parms,
int ctf__add_object(struct ctf *ctf, uint16_t type);
-void ctf__set_strings(struct ctf *ctf, struct gobuffer *strings);
+void ctf__set_strings(struct ctf *ctf, struct strings *strings);
int ctf__encode(struct ctf *ctf, uint8_t flags);
char *ctf__string(struct ctf *ctf, uint32_t ref);
diff --git a/strings.c b/strings.c
index ddb2b1bd85b5..45f8faaeb15d 100644
--- a/strings.c
+++ b/strings.c
@@ -15,75 +15,41 @@
#include <zlib.h>
#include "dutil.h"
+#include "lib/bpf/src/libbpf.h"
struct strings *strings__new(void)
{
struct strings *strs = malloc(sizeof(*strs));
- if (strs != NULL) {
- strs->tree = NULL;
- gobuffer__init(&strs->gb);
+ if (!strs)
+ return NULL;
+
+ strs->btf = btf__new_empty();
+ if (libbpf_get_error(strs->btf)) {
+ free(strs);
+ return NULL;
}
return strs;
-
-}
-
-static void do_nothing(void *ptr __unused)
-{
}
void strings__delete(struct strings *strs)
{
if (strs == NULL)
return;
- tdestroy(strs->tree, do_nothing);
- __gobuffer__delete(&strs->gb);
+ btf__free(strs->btf);
free(strs);
}
-static strings_t strings__insert(struct strings *strs, const char *s)
-{
- return gobuffer__add(&strs->gb, s, strlen(s) + 1);
-}
-
-struct search_key {
- struct strings *strs;
- const char *str;
-};
-
-static int strings__compare(const void *a, const void *b)
-{
- const struct search_key *key = a;
-
- return strcmp(key->str, key->strs->gb.entries + (unsigned long)b);
-}
-
strings_t strings__add(struct strings *strs, const char *str)
{
- unsigned long *s;
strings_t index;
- struct search_key key = {
- .strs = strs,
- .str = str,
- };
if (str == NULL)
return 0;
- s = tsearch(&key, &strs->tree, strings__compare);
- if (s != NULL) {
- if (*(struct search_key **)s == (void *)&key) { /* Not found, replace with the right key */
- index = strings__insert(strs, str);
- if (index != 0)
- *s = (unsigned long)index;
- else {
- tdelete(&key, &strs->tree, strings__compare);
- return 0;
- }
- } else /* Found! */
- index = *s;
- } else
+ index = btf__add_str(strs->btf, str);
+ if (index < 0)
return 0;
return index;
@@ -91,21 +57,32 @@ strings_t strings__add(struct strings *strs, const char *str)
strings_t strings__find(struct strings *strs, const char *str)
{
- strings_t *s;
- struct search_key key = {
- .strs = strs,
- .str = str,
- };
+ return btf__find_str(strs->btf, str);
+}
- if (str == NULL)
- return 0;
+/* a horrible and inefficient hack to get string section size out of BTF */
+strings_t strings__size(const struct strings *strs)
+{
+ const struct btf_header *p;
+ uint32_t sz;
+
+ p = btf__get_raw_data(strs->btf, &sz);
+ if (!p)
+ return -1;
- s = tfind(&key, &strs->tree, strings__compare);
- return s ? *s : 0;
+ return p->str_len;
}
-int strings__cmp(const struct strings *strs, strings_t a, strings_t b)
+/* similarly horrible hack to copy out string section out of BTF */
+int strings__copy(const struct strings *strs, void *dst)
{
- return a == b ? 0 : strcmp(strings__ptr(strs, a),
- strings__ptr(strs, b));
+ const struct btf_header *p;
+ uint32_t sz;
+
+ p = btf__get_raw_data(strs->btf, &sz);
+ if (!p)
+ return -1;
+
+ memcpy(dst, (void *)p + p->str_off, p->str_len);
+ return 0;
}
diff --git a/strings.h b/strings.h
index 01f50efd7adb..522fbf21de0d 100644
--- a/strings.h
+++ b/strings.h
@@ -6,13 +6,12 @@
Copyright (C) 2008 Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
*/
-#include "gobuffer.h"
+#include "lib/bpf/src/btf.h"
typedef unsigned int strings_t;
struct strings {
- void *tree;
- struct gobuffer gb;
+ struct btf *btf;
};
struct strings *strings__new(void);
@@ -21,33 +20,12 @@ void strings__delete(struct strings *strings);
strings_t strings__add(struct strings *strings, const char *str);
strings_t strings__find(struct strings *strings, const char *str);
-
-int strings__cmp(const struct strings *strings, strings_t a, strings_t b);
+strings_t strings__size(const struct strings *strings);
+int strings__copy(const struct strings *strings, void *dst);
static inline const char *strings__ptr(const struct strings *strings, strings_t s)
{
- return gobuffer__ptr(&strings->gb, s);
-}
-
-static inline const char *strings__entries(const struct strings *strings)
-{
- return gobuffer__entries(&strings->gb);
-}
-
-static inline unsigned int strings__nr_entries(const struct strings *strings)
-{
- return gobuffer__nr_entries(&strings->gb);
-}
-
-static inline strings_t strings__size(const struct strings *strings)
-{
- return gobuffer__size(&strings->gb);
-}
-
-static inline const char *strings__compress(struct strings *strings,
- unsigned int *size)
-{
- return gobuffer__compress(&strings->gb, size);
+ return btf__str_by_offset(strings->btf, s);
}
#endif /* _STRINGS_H_ */
--
2.24.1
