From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: [PATCH v5 0/6] Use introsort for qsort
Date: Thu, 13 Jul 2023 10:25:34 -0300 [thread overview]
Message-ID: <20230713132540.2854320-1-adhemerval.zanella@linaro.org> (raw)
The main motivation to use introsort is to make it fully AS-Safe and
AC-Safe, with a limited stack size requirement, to remove the use
of malloc (which troublesome since it seems some program do longjmp
from the callback comparison program), and keep worst-case scenario
bounded to O(n*ln(n)) (instead of potentially quadradic as for the
quicksort).
The implementation does not aim to be the state-of-the-art sort
algorithm, rather I used a well understood introsort (used on
libstdc++, for instance) and leverage the current quicksort
implementation along with a heapsort one from Linux kernel.
Performance-wise, the introsort does fall short compare to
mergesort [1]. I have not added the benchmark because I see that
this should not be focus of this patch. I have added some simple
optimization, also used by Linux kernel heapsort.
Changes from v4
- Use enum for swap function selection.
- Simplify is_aligned.
- Renamed insertsort.
[1] https://sourceware.org/pipermail/libc-alpha/2021-September/130698.html
Adhemerval Zanella (6):
stdlib: Optimization qsort{_r} swap implementation
stdlib: Move insertion sort out qsort
stdlib: qsort: Move some macros to inline function
stdlib: Implement introsort with qsort (BZ 19305)
stdlib: Remove use of mergesort on qsort (BZ 21719)
stdlib: Add more qsort{_r} coverage
include/stdlib.h | 2 -
manual/argp.texi | 2 +-
manual/locale.texi | 3 +-
manual/search.texi | 7 +-
stdlib/Makefile | 3 +-
stdlib/msort.c | 309 ----------------------------------------
stdlib/qsort.c | 337 +++++++++++++++++++++++++++++++++-----------
stdlib/tst-qsort3.c | 298 +++++++++++++++++++++++++++++++++++++++
8 files changed, 562 insertions(+), 399 deletions(-)
delete mode 100644 stdlib/msort.c
create mode 100644 stdlib/tst-qsort3.c
--
2.34.1
next reply other threads:[~2023-07-13 13:25 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-13 13:25 Adhemerval Zanella [this message]
2023-07-13 13:25 ` [PATCH v5 1/6] stdlib: Optimization qsort{_r} swap implementation Adhemerval Zanella
2023-07-13 22:17 ` Paul Eggert
2023-07-14 1:01 ` Paul Eggert
2023-07-14 12:06 ` Adhemerval Zanella Netto
2023-07-17 16:57 ` Alexander Monakov
2023-07-17 17:29 ` Paul Eggert
2023-07-17 18:07 ` Adhemerval Zanella Netto
2023-07-17 18:58 ` Paul Eggert
2023-07-17 19:06 ` Adhemerval Zanella Netto
2023-07-18 14:01 ` Adhemerval Zanella Netto
2023-07-18 14:13 ` Adhemerval Zanella Netto
2023-07-13 13:25 ` [PATCH v5 2/6] stdlib: Move insertion sort out qsort Adhemerval Zanella
2023-07-13 13:25 ` [PATCH v5 3/6] stdlib: qsort: Move some macros to inline function Adhemerval Zanella
2023-07-13 13:25 ` [PATCH v5 4/6] stdlib: Implement introsort with qsort (BZ 19305) Adhemerval Zanella
2023-07-13 13:25 ` [PATCH v5 5/6] stdlib: Remove use of mergesort on qsort (BZ 21719) Adhemerval Zanella
2023-07-13 13:25 ` [PATCH v5 6/6] stdlib: Add more qsort{_r} coverage Adhemerval Zanella
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