From owner-svn-src-all@freebsd.org Mon Apr 23 22:28:50 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 52E28FACC27; Mon, 23 Apr 2018 22:28:50 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 05A257905E; Mon, 23 Apr 2018 22:28:50 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id F07CA236F; Mon, 23 Apr 2018 22:28:49 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w3NMSnWw063631; Mon, 23 Apr 2018 22:28:49 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w3NMSnLS063630; Mon, 23 Apr 2018 22:28:49 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201804232228.w3NMSnLS063630@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Mon, 23 Apr 2018 22:28:49 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r332896 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 332896 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Apr 2018 22:28:50 -0000 Author: mjg Date: Mon Apr 23 22:28:49 2018 New Revision: 332896 URL: https://svnweb.freebsd.org/changeset/base/332896 Log: malloc: stop reading the subzone if MALLOC_DEBUG_MAXZONES == 1 (the default) malloc was showing at the top of profile during while running microbenchmarks. #define DTMALLOC_PROBE_MAX 2 struct malloc_type_internal { uint32_t mti_probes[DTMALLOC_PROBE_MAX]; u_char mti_zone; struct malloc_type_stats mti_stats[MAXCPU]; }; Reading mti_zone it wastes a cacheline to hold mti_probes + mti_zone (which we know is 0) + part of malloc stats of the first cpu which on top induces false-sharing. In particular will-it-scale lock1_processes -t 128 -s 10: before: average:45879692 after: average:51655596 Note the counters can be padded but the right fix is to move them to counter(9), leaving the struct read-only after creation (modulo dtrace probes). Modified: head/sys/kern/kern_malloc.c Modified: head/sys/kern/kern_malloc.c ============================================================================== --- head/sys/kern/kern_malloc.c Mon Apr 23 21:10:33 2018 (r332895) +++ head/sys/kern/kern_malloc.c Mon Apr 23 22:28:49 2018 (r332896) @@ -296,22 +296,49 @@ SYSCTL_UINT(_debug_malloc, OID_AUTO, zone_offset, CTLF &zone_offset, 0, "Separate malloc types by examining the " "Nth character in the malloc type short description."); -static u_int -mtp_get_subzone(const char *desc) +static void +mtp_set_subzone(struct malloc_type *mtp) { + struct malloc_type_internal *mtip; + const char *desc; size_t len; u_int val; + mtip = mtp->ks_handle; + desc = mtp->ks_shortdesc; if (desc == NULL || (len = strlen(desc)) == 0) - return (0); - val = desc[zone_offset % len]; - return (val % numzones); + val = 0; + else + val = desc[zone_offset % len]; + mtip->mti_zone = (val % numzones); } + +static inline u_int +mtp_get_subzone(struct malloc_type *mtp) +{ + struct malloc_type_internal *mtip; + + mtip = mtp->ks_handle; + + KASSERT(mtip->mti_zone < numzones, + ("mti_zone %u out of range %d", + mtip->mti_zone, numzones)); + return (mtip->mti_zone); +} #elif MALLOC_DEBUG_MAXZONES == 0 #error "MALLOC_DEBUG_MAXZONES must be positive." #else +static void +mtp_set_subzone(struct malloc_type *mtp) +{ + struct malloc_type_internal *mtip; + + mtip = mtp->ks_handle; + mtip->mti_zone = 0; +} + static inline u_int -mtp_get_subzone(const char *desc) +mtp_get_subzone(struct malloc_type *mtp) { return (0); @@ -521,7 +548,6 @@ void * malloc(size_t size, struct malloc_type *mtp, int flags) { int indx; - struct malloc_type_internal *mtip; caddr_t va; uma_zone_t zone; #if defined(DEBUG_REDZONE) @@ -534,14 +560,10 @@ malloc(size_t size, struct malloc_type *mtp, int flags #endif if (size <= kmem_zmax) { - mtip = mtp->ks_handle; if (size & KMEM_ZMASK) size = (size & ~KMEM_ZMASK) + KMEM_ZBASE; indx = kmemsize[size >> KMEM_ZSHIFT]; - KASSERT(mtip->mti_zone < numzones, - ("mti_zone %u out of range %d", - mtip->mti_zone, numzones)); - zone = kmemzones[indx].kz_zone[mtip->mti_zone]; + zone = kmemzones[indx].kz_zone[mtp_get_subzone(mtp)]; #ifdef MALLOC_PROFILE krequests[size >> KMEM_ZSHIFT]++; #endif @@ -571,7 +593,6 @@ malloc_domain(size_t size, struct malloc_type *mtp, in int flags) { int indx; - struct malloc_type_internal *mtip; caddr_t va; uma_zone_t zone; #if defined(DEBUG_REDZONE) @@ -583,14 +604,10 @@ malloc_domain(size_t size, struct malloc_type *mtp, in return (va); #endif if (size <= kmem_zmax) { - mtip = mtp->ks_handle; if (size & KMEM_ZMASK) size = (size & ~KMEM_ZMASK) + KMEM_ZBASE; indx = kmemsize[size >> KMEM_ZSHIFT]; - KASSERT(mtip->mti_zone < numzones, - ("mti_zone %u out of range %d", - mtip->mti_zone, numzones)); - zone = kmemzones[indx].kz_zone[mtip->mti_zone]; + zone = kmemzones[indx].kz_zone[mtp_get_subzone(mtp)]; #ifdef MALLOC_PROFILE krequests[size >> KMEM_ZSHIFT]++; #endif @@ -973,7 +990,7 @@ malloc_init(void *data) mtip = uma_zalloc(mt_zone, M_WAITOK | M_ZERO); mtp->ks_handle = mtip; - mtip->mti_zone = mtp_get_subzone(mtp->ks_shortdesc); + mtp_set_subzone(mtp); mtx_lock(&malloc_mtx); mtp->ks_next = kmemstatistics;