From: Stephen Hemminger <stephen@networkplumber.org>
To: dev@dpdk.org
Cc: Stephen Hemminger <stephen@networkplumber.org>, pbhagavatula@marvell.com
Subject: [PATCH v2] eal: avoid issues in macro expansion of alignment
Date: Mon, 3 Jul 2023 16:23:57 -0700 [thread overview]
Message-ID: <20230703232357.122084-1-stephen@networkplumber.org> (raw)
In-Reply-To: <20230703185551.57908-1-stephen@networkplumber.org>
RTE_ALIGN_MUL_NEAR is a macro so the cycle argument could
get evaluated twice causing some potential skew. Fix by
computing value once.
Suggested by patch to fix side effects.
Fixes: 5cbd14b3e5f9 ("eal: roundup TSC frequency when estimating")
Cc: pbhagavatula@marvell.com
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
v2 - fix spelling error in commit message
lib/eal/common/eal_common_timer.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/lib/eal/common/eal_common_timer.c b/lib/eal/common/eal_common_timer.c
index 5686a5102b66..05614b0503cf 100644
--- a/lib/eal/common/eal_common_timer.c
+++ b/lib/eal/common/eal_common_timer.c
@@ -42,10 +42,14 @@ estimate_tsc_freq(void)
RTE_LOG(WARNING, EAL, "WARNING: TSC frequency estimated roughly"
" - clock timings may be less accurate.\n");
/* assume that the rte_delay_us_sleep() will sleep for 1 second */
- uint64_t start = rte_rdtsc();
+ uint64_t start, elapsed;
+
+ start = rte_rdtsc();
rte_delay_us_sleep(US_PER_S);
+ elapsed = rte_rdtsc() - start;
+
/* Round up to 10Mhz. 1E7 ~ 10Mhz */
- return RTE_ALIGN_MUL_NEAR(rte_rdtsc() - start, CYC_PER_10MHZ);
+ return RTE_ALIGN_MUL_NEAR(elapsed, CYC_PER_10MHZ);
}
void
--
2.39.2
next prev parent reply other threads:[~2023-07-03 23:24 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-09 17:18 [dpdk-dev] [PATCH 1/2] eal: fix side effects in align mul macros pbhagavatula
2021-05-09 17:18 ` [dpdk-dev] [PATCH 2/2] eal: fix side effects in ptr align macros pbhagavatula
2021-05-09 19:39 ` Stephen Hemminger
2021-05-10 9:50 ` [dpdk-dev] [EXT] " Pavan Nikhilesh Bhagavatula
2021-05-10 13:34 ` David Marchand
2021-05-10 14:02 ` [dpdk-dev] [PATCH v2 1/2] eal: fix side effects in align mul macros pbhagavatula
2021-05-10 14:02 ` [dpdk-dev] [PATCH v2 2/2] eal: fix side effects in ptr align macros pbhagavatula
2021-05-10 19:40 ` [dpdk-dev] [PATCH v3 1/2] eal: fix side effects in align mul macros pbhagavatula
2021-05-10 19:40 ` [dpdk-dev] [PATCH v3 2/2] eal: fix side effects in ptr align macros pbhagavatula
2021-05-11 2:12 ` Wang, Haiyue
2021-05-11 8:44 ` Pavan Nikhilesh Bhagavatula
2021-05-12 1:13 ` Wang, Haiyue
2023-07-03 18:55 ` [PATCH] eal: avoid issues in macro expansion of alignment Stephen Hemminger
2023-07-03 23:23 ` Stephen Hemminger [this message]
2023-07-04 8:43 ` [PATCH v2] " Morten Brørup
2023-07-04 16:00 ` Stephen Hemminger
2023-07-04 22:16 ` Morten Brørup
2023-07-14 16:37 ` Stephen Hemminger
2023-07-04 16:01 ` [dpdk-dev] [PATCH v3 1/2] eal: fix side effects in align mul macros Stephen Hemminger
-- strict thread matches above, loose matches on Subject: below --
2023-07-14 21:11 [PATCH v2] eal: avoid issues in macro expansion of alignment Morten Brørup
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