Re: [dpdk-dev] [PATCH v3 1/3] lib/lpm: not inline unnecessary functions

Fri, 28 Jun 2019 06:48:16 -0700 

Hi all,

On 28/06/2019 05:34, Stephen Hemminger wrote:

On Fri, 28 Jun 2019 02:44:54 +0000
"Ruifeng Wang (Arm Technology China)"<ruifeng.w...@arm.com>  wrote:


Tests showed that the function inlining caused performance drop on
some x86 platforms with the memory ordering patches applied.
By force no-inline functions, the performance was better than before
on x86 and no impact to arm64 platforms.

Suggested-by: Medvedkin Vladimir<vladimir.medved...@intel.com>
Signed-off-by: Ruifeng Wang<ruifeng.w...@arm.com>
Reviewed-by: Gavin Hu<gavin...@arm.com> 
  {

Do you actually need to force noinline or is just taking of inline enough?
In general, letting compiler decide is often best practice.

The force noinline is an optimization for x86 platforms to keep rte_lpm_add() 
API
performance with memory ordering applied.

I don't think you answered my question. What does a recent version of GCC do
if you drop the inline.

Actually all the functions in rte_lpm should drop inline.
I'm agree with Stephen. If it is not a fastpath and size of function is not minimal it is good to remove inline qualifier for other control plane functions such as rule_add/delete/find/etc and let the compiler decide to inline it (unless it affects performance). 
diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
index 6b7b28a2e431..ffe07e980864 100644
--- a/lib/librte_lpm/rte_lpm.c
+++ b/lib/librte_lpm/rte_lpm.c
@@ -399,7 +399,7 @@ MAP_STATIC_SYMBOL(void rte_lpm_free(struct rte_lpm *lpm),
   * are stored in the rule table from 0 - 31.
   * NOTE: Valid range for depth parameter is 1 .. 32 inclusive.
   */
-static inline int32_t
+static int32_t
  rule_add_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, uint8_t depth,
        uint8_t next_hop)
  {
@@ -471,7 +471,7 @@ rule_add_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, 
uint8_t depth,
        return rule_index;
  }
-static inline int32_t 
+static int32_t
  rule_add_v1604(struct rte_lpm *lpm, uint32_t ip_masked, uint8_t depth,
        uint32_t next_hop)
  {
@@ -547,7 +547,7 @@ rule_add_v1604(struct rte_lpm *lpm, uint32_t ip_masked, 
uint8_t depth,
   * Delete a rule from the rule table.
   * NOTE: Valid range for depth parameter is 1 .. 32 inclusive.
   */
-static inline void
+static void
  rule_delete_v20(struct rte_lpm_v20 *lpm, int32_t rule_index, uint8_t depth)
  {
        int i;
@@ -570,7 +570,7 @@ rule_delete_v20(struct rte_lpm_v20 *lpm, int32_t 
rule_index, uint8_t depth)
        lpm->rule_info[depth - 1].used_rules--;
  }
-static inline void 
+static void
  rule_delete_v1604(struct rte_lpm *lpm, int32_t rule_index, uint8_t depth)
  {
        int i;
@@ -597,7 +597,7 @@ rule_delete_v1604(struct rte_lpm *lpm, int32_t rule_index, 
uint8_t depth)
   * Finds a rule in rule table.
   * NOTE: Valid range for depth parameter is 1 .. 32 inclusive.
   */
-static inline int32_t
+static int32_t
  rule_find_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, uint8_t depth)
  {
        uint32_t rule_gindex, last_rule, rule_index;
@@ -618,7 +618,7 @@ rule_find_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, 
uint8_t depth)
        return -EINVAL;
  }
-static inline int32_t 
+static int32_t
  rule_find_v1604(struct rte_lpm *lpm, uint32_t ip_masked, uint8_t depth)
  {
        uint32_t rule_gindex, last_rule, rule_index;
@@ -642,7 +642,7 @@ rule_find_v1604(struct rte_lpm *lpm, uint32_t ip_masked, 
uint8_t depth)
  /*
   * Find, clean and allocate a tbl8.
   */
-static inline int32_t
+static int32_t
  tbl8_alloc_v20(struct rte_lpm_tbl_entry_v20 *tbl8)
  {
        uint32_t group_idx; /* tbl8 group index. */
@@ -669,7 +669,7 @@ tbl8_alloc_v20(struct rte_lpm_tbl_entry_v20 *tbl8)
        return -ENOSPC;
  }
-static inline int32_t 
+static int32_t
  tbl8_alloc_v1604(struct rte_lpm_tbl_entry *tbl8, uint32_t number_tbl8s)
  {
        uint32_t group_idx; /* tbl8 group index. */
@@ -709,7 +709,7 @@ tbl8_free_v1604(struct rte_lpm_tbl_entry *tbl8, uint32_t 
tbl8_group_start)
        tbl8[tbl8_group_start].valid_group = INVALID;
  }
-static inline int32_t 
+static int32_t
  add_depth_small_v20(struct rte_lpm_v20 *lpm, uint32_t ip, uint8_t depth,
                uint8_t next_hop)
  {
@@ -777,7 +777,7 @@ add_depth_small_v20(struct rte_lpm_v20 *lpm, uint32_t ip, 
uint8_t depth,
        return 0;
  }
-static inline int32_t 
+static int32_t
  add_depth_small_v1604(struct rte_lpm *lpm, uint32_t ip, uint8_t depth,
                uint32_t next_hop)
  {
@@ -846,7 +846,7 @@ add_depth_small_v1604(struct rte_lpm *lpm, uint32_t ip, 
uint8_t depth,
        return 0;
  }
-static inline int32_t 
+static int32_t
  add_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, uint8_t depth,
                uint8_t next_hop)
  {
@@ -971,7 +971,7 @@ add_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t 
ip_masked, uint8_t depth,
        return 0;
  }
-static inline int32_t 
+static int32_t
  add_depth_big_v1604(struct rte_lpm *lpm, uint32_t ip_masked, uint8_t depth,
                uint32_t next_hop)
  {
@@ -1244,7 +1244,7 @@ BIND_DEFAULT_SYMBOL(rte_lpm_is_rule_present, _v1604, 
16.04);
  MAP_STATIC_SYMBOL(int rte_lpm_is_rule_present(struct rte_lpm *lpm, uint32_t 
ip,
                uint8_t depth, uint32_t *next_hop), 
rte_lpm_is_rule_present_v1604);
-static inline int32_t 
+static int32_t
  find_previous_rule_v20(struct rte_lpm_v20 *lpm, uint32_t ip, uint8_t depth,
                uint8_t *sub_rule_depth)
  {
@@ -1266,7 +1266,7 @@ find_previous_rule_v20(struct rte_lpm_v20 *lpm, uint32_t 
ip, uint8_t depth,
        return -1;
  }
-static inline int32_t 
+static int32_t
  find_previous_rule_v1604(struct rte_lpm *lpm, uint32_t ip, uint8_t depth,
                uint8_t *sub_rule_depth)
  {
@@ -1288,7 +1288,7 @@ find_previous_rule_v1604(struct rte_lpm *lpm, uint32_t 
ip, uint8_t depth,
        return -1;
  }
-static inline int32_t 
+static int32_t
  delete_depth_small_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked,
        uint8_t depth, int32_t sub_rule_index, uint8_t sub_rule_depth)
  {
@@ -1381,7 +1381,7 @@ delete_depth_small_v20(struct rte_lpm_v20 *lpm, uint32_t 
ip_masked,
        return 0;
  }
-static inline int32_t 
+static int32_t
  delete_depth_small_v1604(struct rte_lpm *lpm, uint32_t ip_masked,
        uint8_t depth, int32_t sub_rule_index, uint8_t sub_rule_depth)
  {
@@ -1483,7 +1483,7 @@ delete_depth_small_v1604(struct rte_lpm *lpm, uint32_t 
ip_masked,
   * Return of value > -1 means tbl8 is in use but has all the same values and
   * thus can be recycled
   */
-static inline int32_t
+static int32_t
  tbl8_recycle_check_v20(struct rte_lpm_tbl_entry_v20 *tbl8,
                uint32_t tbl8_group_start)
  {
@@ -1530,7 +1530,7 @@ tbl8_recycle_check_v20(struct rte_lpm_tbl_entry_v20 *tbl8,
        return -EINVAL;
  }
-static inline int32_t 
+static int32_t
  tbl8_recycle_check_v1604(struct rte_lpm_tbl_entry *tbl8,
                uint32_t tbl8_group_start)
  {
@@ -1577,7 +1577,7 @@ tbl8_recycle_check_v1604(struct rte_lpm_tbl_entry *tbl8,
        return -EINVAL;
  }
-static inline int32_t 
+static int32_t
  delete_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked,
        uint8_t depth, int32_t sub_rule_index, uint8_t sub_rule_depth)
  {
@@ -1655,7 +1655,7 @@ delete_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t 
ip_masked,
        return 0;
  }
-static inline int32_t 
+static int32_t
  delete_depth_big_v1604(struct rte_lpm *lpm, uint32_t ip_masked,
        uint8_t depth, int32_t sub_rule_index, uint8_t sub_rule_depth)
  {


--
Regards,
Vladimir

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