From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org,
Noah Goldstein <goldstein.w.n@gmail.com>,
Paul Eggert <eggert@cs.ucla.edu>,
Florian Weimer <fweimer@redhat.com>
Subject: [PATCH v8 0/7] Use introsort for qsort
Date: Mon, 2 Oct 2023 16:33:04 -0300 [thread overview]
Message-ID: <20231002193311.3985890-1-adhemerval.zanella@linaro.org> (raw)
The motivation for using introsort is to make it fully AS-safe and
AC-Safe, with a limited stack size requirement, to remove the use of
malloc (which is troublesome since it seems some programs 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, instead it uses used a well-understood introsort (used on
libstdc++, for instance) and leveraged the current quicksort
implementation along with a heapsort one from Linux kernel.
Performance-wise, the introsort does fall short compared to the
mergesort [1]. I have not added a benchmark because I think this should
not be the focus of this patch.
Changes from v7:
- Move __memswap to a static inline on its own header.
- Improve some comments.
Changes from v6:
- Added internal __memswap symbol.
- Improved tst-qsort3 with a reference implementation and a new
duplicated input.
Changes from v5:
- Rewrite heapsort to a custom implementation.
- Use may_alias attribute on swap optimization.
Changes from v4
- Use enum for swap function selection.
- Simplify is_aligned.
- Renamed insertsort.
Adhemerval Zanella (7):
string: Add internal memswap implementation
stdlib: Optimization qsort{_r} swap implementation
stdlib: Move insertion sort out qsort
stdlib: qsort: Move some macros to inline function
stdlib: Implement introsort for qsort (BZ 19305)
stdlib: Remove use of mergesort on qsort (BZ 21719)
stdlib: Add more qsort{_r} coverage
include/stdlib.h | 2 -
include/string.h | 3 +
manual/argp.texi | 2 +-
manual/locale.texi | 3 +-
manual/search.texi | 7 +-
stdlib/Makefile | 3 +-
stdlib/msort.c | 309 -----------------------------------
stdlib/qsort.c | 315 +++++++++++++++++++++++++++---------
stdlib/tst-qsort3.c | 366 ++++++++++++++++++++++++++++++++++++++++++
string/Makefile | 13 ++
string/memswap.c | 41 +++++
string/test-memswap.c | 191 ++++++++++++++++++++++
12 files changed, 856 insertions(+), 399 deletions(-)
delete mode 100644 stdlib/msort.c
create mode 100644 stdlib/tst-qsort3.c
create mode 100644 string/memswap.c
create mode 100644 string/test-memswap.c
--
2.34.1
next reply other threads:[~2023-10-02 19:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-02 19:33 Adhemerval Zanella [this message]
2023-10-02 19:33 ` [PATCH v8 1/7] string: Add internal memswap implementation Adhemerval Zanella
2023-10-03 5:43 ` Noah Goldstein
2023-10-03 11:00 ` Adhemerval Zanella Netto
2023-10-02 19:33 ` [PATCH v8 2/7] stdlib: Optimization qsort{_r} swap implementation Adhemerval Zanella
2023-10-02 19:33 ` [PATCH v8 3/7] stdlib: Move insertion sort out qsort Adhemerval Zanella
2023-10-02 19:33 ` [PATCH v8 4/7] stdlib: qsort: Move some macros to inline function Adhemerval Zanella
2023-10-02 19:33 ` [PATCH v8 5/7] stdlib: Implement introsort for qsort (BZ 19305) Adhemerval Zanella
2023-10-02 19:33 ` [PATCH v8 6/7] stdlib: Remove use of mergesort on qsort (BZ 21719) Adhemerval Zanella
2023-10-02 19:33 ` [PATCH v8 7/7] stdlib: Add more qsort{_r} coverage Adhemerval Zanella
2023-10-03 12:22 [PATCH v8 0/7] Use introsort for qsort Adhemerval Zanella
2023-10-03 18:13 ` Noah Goldstein
2023-10-27 20:24 ` Adhemerval Zanella Netto
2023-10-28 1:31 ` Noah Goldstein
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