From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by sourceware.org (Postfix) with ESMTPS id B9F7B3857800 for ; Mon, 14 Sep 2020 09:23:01 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org B9F7B3857800 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=rguenther@suse.de X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E3E02B244; Mon, 14 Sep 2020 09:23:15 +0000 (UTC) Date: Mon, 14 Sep 2020 11:23:00 +0200 (CEST) From: Richard Biener To: Jakub Jelinek cc: Jan Hubicka , gcc-patches@gcc.gnu.org, "Joseph S. Myers" Subject: Re: [PATCH] options, lto: Optimize streaming of optimization nodes In-Reply-To: <20200914084810.GU21814@tucnak> Message-ID: References: <20200913083327.GG21814@tucnak> <20200914070048.GT21814@tucnak> <20200914084810.GU21814@tucnak> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 X-Spam-Status: No, score=-5.1 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Sep 2020 09:23:03 -0000 On Mon, 14 Sep 2020, Jakub Jelinek wrote: > On Mon, Sep 14, 2020 at 09:31:52AM +0200, Richard Biener wrote: > > But does it make any noticable difference in the end? Using > > Yes. > > > bp_pack_var_len_unsigned just causes us to [u]leb encode half-bytes > > rather than full bytes. Using hardcoded 8/16/32/64 makes it still > > dependent on what 'int' is at maximum on the host. > > > > That is, I'd indeed prefer bp_pack_var_len_unsigned over hard-coding > > 8, 16, etc., but can you share a size comparison of the bitpack? > > I guess with bp_pack_var_len_unsigned it might shrink in half > > compared to the current code and streaming standard -O2? > > So, I've tried > --- gcc/tree-streamer-out.c.jj 2020-07-28 15:39:10.079755251 +0200 > +++ gcc/tree-streamer-out.c 2020-09-14 10:31:29.106957258 +0200 > @@ -489,7 +489,11 @@ streamer_write_tree_bitfields (struct ou > pack_ts_translation_unit_decl_value_fields (ob, &bp, expr); > > if (CODE_CONTAINS_STRUCT (code, TS_OPTIMIZATION)) > +{ > +long ts = ob->main_stream->total_size; > cl_optimization_stream_out (ob, &bp, TREE_OPTIMIZATION (expr)); > +fprintf (stderr, "total_size %ld\n", (long) (ob->main_stream->total_size - ts)); > +} > > if (CODE_CONTAINS_STRUCT (code, TS_CONSTRUCTOR)) > bp_pack_var_len_unsigned (&bp, CONSTRUCTOR_NELTS (expr)); > hack without and with the following patch on a simple small testcase with > -O2 -flto. > Got 574 bytes without the opc-save-gen.awk change and 454 bytes with it, > that is ~ 21% saving on the TREE_OPTIMIZATION streaming. OK, not spectacular but I guess good enough. So I'd say the below patch using bp_pack_var_len_{int,unsigned} is OK. Thanks, Richard. > 2020-09-14 Jakub Jelinek > > * optc-save-gen.awk: In cl_optimization_stream_out use > bp_pack_var_len_{int,unsigned} instead of bp_pack_value. In > cl_optimization_stream_in use bp_unpack_var_len_{int,unsigned} > instead of bp_unpack_value. Formatting fix. > > --- gcc/optc-save-gen.awk.jj 2020-09-14 09:04:35.879854156 +0200 > +++ gcc/optc-save-gen.awk 2020-09-14 10:38:47.722424942 +0200 > @@ -1257,8 +1257,10 @@ for (i = 0; i < n_opt_val; i++) { > otype = var_opt_val_type[i]; > if (otype ~ "^const char \\**$") > print " bp_pack_string (ob, bp, ptr->" name", true);"; > + else if (otype ~ "^unsigned") > + print " bp_pack_var_len_unsigned (bp, ptr->" name");"; > else > - print " bp_pack_value (bp, ptr->" name", 64);"; > + print " bp_pack_var_len_int (bp, ptr->" name");"; > } > print " for (size_t i = 0; i < sizeof (ptr->explicit_mask) / sizeof (ptr->explicit_mask[0]); i++)"; > print " bp_pack_value (bp, ptr->explicit_mask[i], 64);"; > @@ -1274,14 +1276,15 @@ print "{"; > for (i = 0; i < n_opt_val; i++) { > name = var_opt_val[i] > otype = var_opt_val_type[i]; > - if (otype ~ "^const char \\**$") > - { > - print " ptr->" name" = bp_unpack_string (data_in, bp);"; > - print " if (ptr->" name")"; > - print " ptr->" name" = xstrdup (ptr->" name");"; > + if (otype ~ "^const char \\**$") { > + print " ptr->" name" = bp_unpack_string (data_in, bp);"; > + print " if (ptr->" name")"; > + print " ptr->" name" = xstrdup (ptr->" name");"; > } > + else if (otype ~ "^unsigned") > + print " ptr->" name" = (" var_opt_val_type[i] ") bp_unpack_var_len_unsigned (bp);"; > else > - print " ptr->" name" = (" var_opt_val_type[i] ") bp_unpack_value (bp, 64);"; > + print " ptr->" name" = (" var_opt_val_type[i] ") bp_unpack_var_len_int (bp);"; > } > print " for (size_t i = 0; i < sizeof (ptr->explicit_mask) / sizeof (ptr->explicit_mask[0]); i++)"; > print " ptr->explicit_mask[i] = bp_unpack_value (bp, 64);"; > > > Jakub > > -- Richard Biener SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)