From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:38898) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uc3GU-0000uZ-K3 for qemu-devel@nongnu.org; Mon, 13 May 2013 20:38:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uc3GT-0005kY-Hi for qemu-devel@nongnu.org; Mon, 13 May 2013 20:38:50 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:55495) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uc3GS-0005jx-VV for qemu-devel@nongnu.org; Mon, 13 May 2013 20:38:49 -0400 Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 14 May 2013 10:32:23 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 645642BB0051 for ; Tue, 14 May 2013 10:38:41 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r4E0OgTo17170682 for ; Tue, 14 May 2013 10:24:43 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r4E0cePb019117 for ; Tue, 14 May 2013 10:38:40 +1000 From: Anthony Liguori In-Reply-To: References: <1368477106-7579-1-git-send-email-aliguori@us.ibm.com> Date: Mon, 13 May 2013 19:38:32 -0500 Message-ID: <87ehdal7jr.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: Re: [Qemu-devel] [PATCH for-1.5 1/2] qom: aggressively optimize qom casting List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Paolo Bonzini , qemu-devel@nongnu.org, Aurelien Jarno , Andreas Faerber Peter Maydell writes: > On 13 May 2013 21:31, Anthony Liguori wrote: >> This patch adds a small typename cache to ObjectClass. This allows >> caching positive casts within each ObjectClass. Benchmarking a >> PPC workload provided by Aurelien, this patch eliminates every >> single g_hash_table_lookup() happening during the benchmark (which >> was about 2 million per-second). > > That's a lot of hashtable lookups... I suspect it's due to a cast somewhere in a path checking for pending interrupts or something like that. That would get called quite often. > >> --- a/include/qom/object.h >> +++ b/include/qom/object.h >> @@ -344,6 +344,8 @@ typedef void (ObjectUnparent)(Object *obj); >> */ >> typedef void (ObjectFree)(void *obj); >> >> +#define OBJECT_CLASS_CAST_CACHE 4 > > Total nitpick, but shouldn't this be > OBJECT_CLASS_CAST_CACHE_SIZE ? Ack, I need to respin anyway so I'll make the updates. Thanks, Anthony Liguori > > thanks > -- PMM