From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6252C184E; Wed, 3 Jul 2024 01:24:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719969853; cv=none; b=bSIR3eaapr1ClxZ97fFo3gm+9OA8NqArbYSopy2M1rWyaF73O9eRxt2HDhG5YXVcI8PJZmiZZvBkfkjS6X3XP0kM4KKI2YA62REazaDf0hKl1SowPlDc0E8ay3yi2/b1M3FGEcwBIsGeMl7yg+1ZHf4V+rUbVTkB076uKMi2VRs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719969853; c=relaxed/simple; bh=aT1n/TcfiZA8fO3fOhhChEPt+/wXzY6RutDc7C3ik30=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DkXIxpl/g883mO/82d/bLLmdxqwErBOMWPXtrFCMgl3s0gwIj0JRFsmdUvxpIJz3RFXfXP3ckTK9y2A3aP2vev1FtHJgsD6EW+2y9RVWMhiQkbWxIOHQPybgpEGIwZ3mbnB4jZS9h4G83kZLV/hRZ6mEPSxIWoFpEo98Z2lZhYQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RzoRzgPJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RzoRzgPJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73FA3C116B1; Wed, 3 Jul 2024 01:24:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719969853; bh=aT1n/TcfiZA8fO3fOhhChEPt+/wXzY6RutDc7C3ik30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RzoRzgPJP89Yo11Kfu8CTFoy7kXV83DJdnsWfIud6ESrdQS1dRTgCfLOC8OWIO2o+ cilpDR/c0wAIDnqvMZzv67B85zGBFADy0GcdCS74CLdsUSPbs1e+hADrhaQE2qQ8ge iqqrnaSqpkPWYxMijOq56ixNXp3DizI326GG45mWIzeaMslLY9Lt/tNv2KNltVNfq0 8OOk85kyha2sCWPjpvAiurS6KvzOIC8vOYPeWeSSekjzxMCT9ONE3ZNQAeheOXl67k omghVROweaKJv473hLKvbNwI1Qe3qm26DMF2cOGaGTViAfZVbBY9KPTdowzR5hG/W3 kkb9JUi19lhWA== Date: Tue, 2 Jul 2024 18:24:11 -0700 From: Namhyung Kim To: Athira Rajeev Cc: acme@kernel.org, jolsa@kernel.org, adrian.hunter@intel.com, irogers@google.com, segher@kernel.crashing.org, christophe.leroy@csgroup.eu, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, akanksha@linux.ibm.com, maddy@linux.ibm.com, kjain@linux.ibm.com, disgoel@linux.vnet.ibm.com Subject: Re: [PATCH V5 05/17] tools/perf: Add support to capture and parse raw instruction in powerpc using dso__data_read_offset utility Message-ID: References: <20240701043430.66666-1-atrajeev@linux.vnet.ibm.com> <20240701043430.66666-6-atrajeev@linux.vnet.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240701043430.66666-6-atrajeev@linux.vnet.ibm.com> On Mon, Jul 01, 2024 at 10:04:18AM +0530, Athira Rajeev wrote: > Add support to capture and parse raw instruction in powerpc. > Currently, the perf tool infrastructure uses two ways to disassemble > and understand the instruction. One is objdump and other option is > via libcapstone. > > Currently, the perf tool infrastructure uses "--no-show-raw-insn" option > with "objdump" while disassemble. Example from powerpc with this option > for an instruction address is: > > Snippet from: > objdump --start-address=
--stop-address=
-d --no-show-raw-insn -C > > c0000000010224b4: lwz r10,0(r9) > > This line "lwz r10,0(r9)" is parsed to extract instruction name, > registers names and offset. Also to find whether there is a memory > reference in the operands, "memory_ref_char" field of objdump is used. > For x86, "(" is used as memory_ref_char to tackle instructions of the > form "mov (%rax), %rcx". > > In case of powerpc, not all instructions using "(" are the only memory > instructions. Example, above instruction can also be of extended form (X > form) "lwzx r10,0,r19". Inorder to easy identify the instruction category > and extract the source/target registers, patch adds support to use raw > instruction for powerpc. Approach used is to read the raw instruction > directly from the DSO file using "dso__data_read_offset" utility which > is already implemented in perf infrastructure in "util/dso.c". > > Example: > > 38 01 81 e8 ld r4,312(r1) > > Here "38 01 81 e8" is the raw instruction representation. In powerpc, > this translates to instruction form: "ld RT,DS(RA)" and binary code > as: > > | 58 | RT | RA | DS | | > ------------------------------------- > 0 6 11 16 30 31 > > Function "symbol__disassemble_dso" is updated to read raw instruction > directly from DSO using dso__data_read_offset utility. In case of > above example, this captures: > line: 38 01 81 e8 > > The above works well when perf report is invoked with only sort keys for > data type ie type and typeoff. Because there is no instruction level > annotation needed if only data type information is requested for. For > annotating sample, along with type and typeoff sort key, "sym" sort key > is also needed. And by default invoking just "perf report" uses sort key > "sym" that displays the symbol information. > > With approach changes in powerpc which first reads DSO for raw > instruction, "perf annotate" and "perf report" + a key breaks since > it doesn't do the instruction level disassembly. > > Snippet of result from perf report: > > Samples: 1K of event 'mem-loads', 4000 Hz, Event count (approx.): 937238 > do_work /usr/bin/pmlogger [Percent: local period] > Percent│ ea230010 > │ 3a550010 > │ 3a600000 > > │ 38f60001 > │ 39490008 > │ 42400438 > 51.44 │ 81290008 > │ 7d485378 > > Here, raw instruction is displayed in the output instead of human > readable annotated form. > > One way to get the appropriate data is to specify "--objdump path", by > which code annotation will be done. But the default behaviour will be > changed. To fix this breakage, check if "sym" sort key is set. If so > fallback and use the libcapstone/objdump way of disassmbling the sample. > > With the changes and "perf report" > > Samples: 1K of event 'mem-loads', 4000 Hz, Event count (approx.): 937238 > do_work /usr/bin/pmlogger [Percent: local period] > Percent│ ld r17,16(r3) > │ addi r18,r21,16 > │ li r19,0 > > │ 8b0: rldicl r10,r10,63,33 > │ addi r10,r10,1 > │ mtctr r10 > │ ↓ b 8e4 > │ 8c0: addi r7,r22,1 > │ addi r10,r9,8 > │ ↓ bdz d00 > 51.44 │ lwz r9,8(r9) > │ mr r8,r10 > │ cmpw r20,r9 > > Signed-off-by: Athira Rajeev > --- > tools/perf/util/disasm.c | 101 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 101 insertions(+) > > diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c > index ddb861a0b043..e400dcab4029 100644 > --- a/tools/perf/util/disasm.c > +++ b/tools/perf/util/disasm.c > @@ -25,6 +25,7 @@ > #include "srcline.h" > #include "symbol.h" > #include "util.h" > +#include "sort.h" > > static regex_t file_lineno; > > @@ -1645,6 +1646,91 @@ static int symbol__disassemble_capstone(char *filename, struct symbol *sym, > } > #endif > > +static int symbol__disassemble_dso(char *filename, struct symbol *sym, Again, I still think this should be named to symbol__disassemble_raw() because it only uses the raw binary codes. Using dso__data_read_offset is not important here and it's just a way of implementing it. Thanks, Namhyung > + struct annotate_args *args) > +{ > + struct annotation *notes = symbol__annotation(sym); > + struct map *map = args->ms.map; > + struct dso *dso = map__dso(map); > + u64 start = map__rip_2objdump(map, sym->start); > + u64 end = map__rip_2objdump(map, sym->end); > + u64 len = end - start; > + u64 offset; > + int i, count; > + u8 *buf = NULL; > + char disasm_buf[512]; > + struct disasm_line *dl; > + u32 *line; > + > + /* Return if objdump is specified explicitly */ > + if (args->options->objdump_path) > + return -1; > + > + pr_debug("Reading raw instruction from : %s using dso__data_read_offset\n", filename); > + > + buf = malloc(len); > + if (buf == NULL) > + goto err; > + > + count = dso__data_read_offset(dso, NULL, sym->start, buf, len); > + > + line = (u32 *)buf; > + > + if ((u64)count != len) > + goto err; > + > + /* add the function address and name */ > + scnprintf(disasm_buf, sizeof(disasm_buf), "%#"PRIx64" <%s>:", > + start, sym->name); > + > + args->offset = -1; > + args->line = disasm_buf; > + args->line_nr = 0; > + args->fileloc = NULL; > + args->ms.sym = sym; > + > + dl = disasm_line__new(args); > + if (dl == NULL) > + goto err; > + > + annotation_line__add(&dl->al, ¬es->src->source); > + > + /* Each raw instruction is 4 byte */ > + count = len/4; > + > + for (i = 0, offset = 0; i < count; i++) { > + args->offset = offset; > + sprintf(args->line, "%x", line[i]); > + dl = disasm_line__new(args); > + if (dl == NULL) > + goto err; > + > + annotation_line__add(&dl->al, ¬es->src->source); > + offset += 4; > + } > + > + /* It failed in the middle */ > + if (offset != len) { > + struct list_head *list = ¬es->src->source; > + > + /* Discard all lines and fallback to objdump */ > + while (!list_empty(list)) { > + dl = list_first_entry(list, struct disasm_line, al.node); > + > + list_del_init(&dl->al.node); > + disasm_line__free(dl); > + } > + count = -1; > + } > + > +out: > + free(buf); > + return count < 0 ? count : 0; > + > +err: > + count = -1; > + goto out; > +} > /* > * Possibly create a new version of line with tabs expanded. Returns the > * existing or new line, storage is updated if a new line is allocated. If > @@ -1769,6 +1855,21 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args) > strcpy(symfs_filename, tmp); > } > > + /* > + * For powerpc data type profiling, use the dso__data_read_offset > + * to read raw instruction directly and interpret the binary code > + * to understand instructions and register fields. For sort keys as > + * type and typeoff, disassemble to mnemonic notation is > + * not required in case of powerpc. > + */ > + if (arch__is(args->arch, "powerpc")) { > + if (sort_order && !strstr(sort_order, "sym")) { > + err = symbol__disassemble_dso(symfs_filename, sym, args); > + if (err == 0) > + goto out_remove_tmp; > + } > + } > + > #ifdef HAVE_LIBCAPSTONE_SUPPORT > err = symbol__disassemble_capstone(symfs_filename, sym, args); > if (err == 0) > -- > 2.43.0 >