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From: Stanislaw Kardach <kda@semihalf.com>
To: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Cc: Stanislaw Kardach <kda@semihalf.com>,
	dev@dpdk.org, Frank Zhao <Frank.Zhao@starfivetech.com>,
	Sam Grove <sam.grove@sifive.com>,
	mw@semihalf.com, upstream@semihalf.com
Subject: [PATCH 1/1] test/ring: remove excessive inlining
Date: Tue, 10 May 2022 13:57:58 +0200	[thread overview]
Message-ID: <20220510115758.457794-1-kda@semihalf.com> (raw)

Forcing inlining in test_ring_enqueue and test_ring_dequeue can cause
the compiled code to grow extensively when compiled with no optimization
(-O0 or -Og). This is default in the meson's debug configuration. This
can collide with compiler bugs and cause issues during linking of unit
tests where the api_type or esize are non-const variables causing
inlining cascade. In perf tests this is not the case in perf-tests as
esize and api_type are const values.

One such case was discovered when porting DPDK to RISC-V. GCC 11.2 (and
no fix still in 12.1) is generating a short relative jump instruction
(J <offset>) for goto and for loops. When loop body grows extensively in
ring test, the target offset goes beyond supported offfset of +/- 1MB
from PC. This is an obvious bug in the GCC as RISC-V has a
two-instruction construct to jump to any absolute address (AUIPC+JALR).

However there is no reason to force inlining as the test code works
perfectly fine without it.

Fixes: a9fe152363 test/ring: add custom element size functional tests

Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
---
 app/test/test_ring.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/app/test/test_ring.h b/app/test/test_ring.h
index c8bfec8399..45c263f3ff 100644
--- a/app/test/test_ring.h
+++ b/app/test/test_ring.h
@@ -97,7 +97,7 @@ test_ring_copy_from(struct rte_ring_zc_data *zcd, void *dst, int esize,
 	}
 }
 
-static __rte_always_inline unsigned int
+static inline unsigned int
 test_ring_enqueue(struct rte_ring *r, void **obj, int esize, unsigned int n,
 			unsigned int api_type)
 {
@@ -158,7 +158,7 @@ test_ring_enqueue(struct rte_ring *r, void **obj, int esize, unsigned int n,
 		}
 }
 
-static __rte_always_inline unsigned int
+static inline unsigned int
 test_ring_dequeue(struct rte_ring *r, void **obj, int esize, unsigned int n,
 			unsigned int api_type)
 {
@@ -222,7 +222,7 @@ test_ring_dequeue(struct rte_ring *r, void **obj, int esize, unsigned int n,
 /* This function is placed here as it is required for both
  * performance and functional tests.
  */
-static __rte_always_inline void *
+static inline void *
 test_ring_calloc(unsigned int rsize, int esize)
 {
 	unsigned int sz;
-- 
2.30.2

             reply	other threads:[~2022-05-10 11:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-10 11:57 Stanislaw Kardach [this message]
2022-05-10 23:23 ` Honnappa Nagarahalli
2022-05-11  9:14   ` Bruce Richardson
2022-05-11 14:39   ` Stanisław Kardach
2022-05-11 15:07 ` [PATCH v2 " Stanislaw Kardach
2022-05-11 15:48   ` Bruce Richardson
2022-05-23 13:31     ` David Marchand
2022-05-11 16:51   ` Honnappa Nagarahalli
2022-05-19 22:50   ` Konstantin Ananyev

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