From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752175AbcHFWlj (ORCPT ); Sat, 6 Aug 2016 18:41:39 -0400 Received: from smtprelay0164.hostedemail.com ([216.40.44.164]:53162 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751724AbcHFWli (ORCPT ); Sat, 6 Aug 2016 18:41:38 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::,RULES_HIT:41:69:355:379:541:599:988:989:1260:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2559:2562:2828:3138:3139:3140:3141:3142:3353:3622:3865:3867:3868:3871:4321:5007:8957:10004:10400:10848:11026:11232:11658:11783:11914:12043:12291:12296:12517:12519:12683:12740:13069:13311:13357:13439:13894:14659:14721:21080:21433:30045:30046:30054:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: sheet42_2b06ba6001b5c X-Filterd-Recvd-Size: 2432 Message-ID: <1470523294.28648.33.camel@perches.com> Subject: Re: [PATCH] proc: faster /proc/*/status From: Joe Perches To: Alexey Dobriyan , akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org Date: Sat, 06 Aug 2016 15:41:34 -0700 In-Reply-To: <20160806125608.GB1187@p183.telecom.by> References: <20160806125608.GB1187@p183.telecom.by> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.18.5.2-0ubuntu3 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2016-08-06 at 15:56 +0300, Alexey Dobriyan wrote: > top(1) opens the following files for every PID: > > /proc/*/stat > /proc/*/statm > /proc/*/status > > This patch switches /proc/*/status away from seq_printf(). > The result is 13.5% speedup. If this is really an important consideration, perhaps seq_put_decimal_ull (_ll too) should be changed from void seq_put_decimal_ull(seq_file *, char, unsigned long long) to void seq_put_decimal_ull(seq_file *, const char *, unsigned long) > fs/proc/array.c |   87 ++++++++++++++++++++++++++++++-------------------------- [] > @@ -186,51 +186,52 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, >   task_unlock(p); >   rcu_read_unlock(); >   > - seq_printf(m, > - "State:\t%s\n" > - "Tgid:\t%d\n" > - "Ngid:\t%d\n" > - "Pid:\t%d\n" > - "PPid:\t%d\n" > - "TracerPid:\t%d\n" > - "Uid:\t%d\t%d\t%d\t%d\n" > - "Gid:\t%d\t%d\t%d\t%d\n" > - "FDSize:\t%d\nGroups:\t", > - get_task_state(p), > - tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid, > - from_kuid_munged(user_ns, cred->uid), > - from_kuid_munged(user_ns, cred->euid), > - from_kuid_munged(user_ns, cred->suid), > - from_kuid_munged(user_ns, cred->fsuid), > - from_kgid_munged(user_ns, cred->gid), > - from_kgid_munged(user_ns, cred->egid), > - from_kgid_munged(user_ns, cred->sgid), > - from_kgid_munged(user_ns, cred->fsgid), > - max_fds); > - > + seq_printf(m, "State:\t%s", get_task_state(p)); > + > + seq_puts(m, "\nTgid:\t"); > + seq_put_decimal_ull(m, 0, tgid); [etc...] Perhaps too the conversions from %d to %llu are inappropriate and seq_put_decimal and seq_put_decimal_u should be added.