Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752745AbcKHVhd (ORCPT ); Tue, 8 Nov 2016 16:37:33 -0500 Received: from mail-pf0-f196.google.com ([209.85.192.196]:35652 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752278AbcKHVhc (ORCPT ); Tue, 8 Nov 2016 16:37:32 -0500 From: Andrei Vagin To: linux-kernel@vger.kernel.org Cc: Andrei Vagin , Andrew Morton , Alexey Dobriyan Subject: [PATCH] proc: optimize render_sigset_t() Date: Tue, 8 Nov 2016 13:37:28 -0800 Message-Id: <1478641048-11406-1-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1920 Lines: 72 render_sigset_t() requires about 30% of time to generate /proc/pid/status. - 74.44% sys_read - 74.40% vfs_read - 74.01% __vfs_read - 73.36% seq_read - 72.97% proc_single_show - 72.26% proc_pid_status + 29.79% render_sigset_t + 11.47% task_mem + 5.60% render_cap_t + 4.95% seq_printf + 4.28% cpuset_task_status_allowed seq_printf is called for each symbol of a signal mask. This patch collect a whole mask in a buffer and prints it for one call of seq_puts(). - 65.02% proc_single_show - 63.75% proc_pid_status + 15.73% task_mem + 7.42% render_sigset_t + 7.39% render_cap_t + 6.46% cpuset_task_status_allowed /proc/pid/status is generated 25% faster with this optimization. Cc: Andrew Morton Cc: Alexey Dobriyan Signed-off-by: Andrei Vagin --- fs/proc/array.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index 81818ad..0190c3e 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -232,11 +232,13 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, void render_sigset_t(struct seq_file *m, const char *header, sigset_t *set) { - int i; + char buf[_NSIG / 4 + 2]; + int i, j; seq_puts(m, header); i = _NSIG; + j = 0; do { int x = 0; @@ -245,10 +247,13 @@ void render_sigset_t(struct seq_file *m, const char *header, if (sigismember(set, i+2)) x |= 2; if (sigismember(set, i+3)) x |= 4; if (sigismember(set, i+4)) x |= 8; - seq_printf(m, "%x", x); + buf[j++] = hex_asc[x]; } while (i >= 4); - seq_putc(m, '\n'); + buf[j++] = '\n'; + buf[j++] = 0; + + seq_puts(m, buf); } static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign, -- 2.7.4