From: Yury Norov <yury.norov@gmail.com>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yury Norov <yury.norov@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-mmc@vger.kernel.org, linux-perf-users@vger.kernel.org,
kvm@vger.kernel.org,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Alexander Lobakin <alobakin@pm.me>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Alexey Klimov <aklimov@redhat.com>,
Andrea Merello <andrea.merello@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Arnd Bergmann <arnd@arndb.de>, Ben Gardon <bgardon@google.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Brian Cain <bcain@codeaurora.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Christoph Lameter <cl@linux.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
David Hildenbrand <david@redhat.com>,
Dennis Zhou <dennis@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Heiko Carstens <hca@linux.ibm.com>,
Ian Rogers <irogers@google.com>, Ingo Molnar <mingo@redhat.com>,
Jaegeuk Kim <jaegeuk@kernel.org>,
Jakub Kicinski <kuba@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Joe Perches <joe@perches.com>, Jonas Bonn <jonas@southpole.se>,
Leo Yan <leo.yan@linaro.org>, Mark Rutland <mark.rutland@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Petr Mladek <pmladek@suse.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Rich Felker <dalias@libc.org>,
Samuel Mendoza-Jonas <sam@mendozajonas.com>,
Sean Christopherson <seanjc@google.com>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Shuah Khan <shuah@kernel.org>,
Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
Steven Rostedt <rostedt@goodmis.org>, Tejun Heo <tj@kernel.org>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Ulf Hansson <ulf.hansson@linaro.org>,
Will Deacon <will@kernel.org>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Yoshinori Sato <ysato@users.sourceforge.jp>
Subject: [PATCH 16/16] vsprintf: rework bitmap_list_string
Date: Mon, 4 Oct 2021 22:40:59 -0700 [thread overview]
Message-ID: <20211005054059.475634-17-yury.norov@gmail.com> (raw)
In-Reply-To: <20211005054059.475634-1-yury.norov@gmail.com>
bitmap_list_string() is very ineffective when printing bitmaps with long
ranges of set bits because it calls find_next_bit for each bit in the
bitmap. We can do better by detecting ranges of set bits.
In my environment, before/after is 943008/31008 ns.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
lib/vsprintf.c | 24 +++++++-----------------
1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index d7ad44f2c8f5..4415bea601fd 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1241,20 +1241,13 @@ char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
struct printf_spec spec, const char *fmt)
{
int nr_bits = max_t(int, spec.field_width, 0);
- /* current bit is 'cur', most recently seen range is [rbot, rtop] */
- int cur, rbot, rtop;
bool first = true;
+ int rbot, rtop;
if (check_pointer(&buf, end, bitmap, spec))
return buf;
- rbot = cur = find_first_bit(bitmap, nr_bits);
- while (cur < nr_bits) {
- rtop = cur;
- cur = find_next_bit(bitmap, nr_bits, cur + 1);
- if (cur < nr_bits && cur <= rtop + 1)
- continue;
-
+ for_each_set_bitrange(rbot, rtop, bitmap, nr_bits) {
if (!first) {
if (buf < end)
*buf = ',';
@@ -1263,15 +1256,12 @@ char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
first = false;
buf = number(buf, end, rbot, default_dec_spec);
- if (rbot < rtop) {
- if (buf < end)
- *buf = '-';
- buf++;
-
- buf = number(buf, end, rtop, default_dec_spec);
- }
+ if (rtop == rbot + 1)
+ continue;
- rbot = cur;
+ if (buf < end)
+ *buf = '-';
+ buf = number(++buf, end, rtop - 1, default_dec_spec);
}
return buf;
}
--
2.30.2
next prev parent reply other threads:[~2021-10-05 5:43 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 5:40 [PATCH RESEND 3 00/16] Bitmap patches for 5.15 Yury Norov
2021-10-05 5:40 ` [PATCH 01/16] bitops: protect find_first_{,zero}_bit properly Yury Norov
2021-10-05 5:40 ` [PATCH 02/16] bitops: move find_bit_*_le functions from le.h to find.h Yury Norov
2021-10-05 5:40 ` [PATCH 03/16] include: move find.h from asm_generic to linux Yury Norov
2021-10-05 5:40 ` [PATCH 04/16] arch: remove GENERIC_FIND_FIRST_BIT entirely Yury Norov
2021-10-05 5:40 ` [PATCH 05/16] lib: add find_first_and_bit() Yury Norov
2021-10-05 5:40 ` [PATCH 06/16] cpumask: use find_first_and_bit() Yury Norov
2021-10-05 5:40 ` [PATCH 07/16] all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate Yury Norov
2021-10-05 5:40 ` [PATCH 08/16] tools: sync tools/bitmap with mother linux Yury Norov
2021-10-05 5:40 ` [PATCH 09/16] cpumask: replace cpumask_next_* with cpumask_first_* where appropriate Yury Norov
2021-10-05 5:40 ` [PATCH 10/16] include/linux: move for_each_bit() macros from bitops.h to find.h Yury Norov
2021-10-05 5:40 ` [PATCH 11/16] find: micro-optimize for_each_{set,clear}_bit() Yury Norov
2021-10-05 5:40 ` [PATCH 12/16] Replace for_each_*_bit_from() with for_each_*_bit() where appropriate Yury Norov
2021-10-05 5:40 ` [PATCH 13/16] mm/percpu: micro-optimize pcpu_is_populated() Yury Norov
2021-10-05 5:40 ` [PATCH 14/16] bitmap: unify find_bit operations Yury Norov
2021-10-05 5:40 ` [PATCH 15/16] lib: bitmap: add performance test for bitmap_print_to_pagebuf Yury Norov
2021-10-05 5:40 ` Yury Norov [this message]
2021-10-05 6:02 ` [PATCH RESEND 3 00/16] Bitmap patches for 5.15 Stephen Rothwell
-- strict thread matches above, loose matches on Subject: below --
2021-10-01 18:12 [PATCH RESEND 2 00/16] Resend bitmap patches Yury Norov
2021-10-01 18:12 ` [PATCH 16/16] vsprintf: rework bitmap_list_string Yury Norov
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