From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54DC5C00A89 for ; Mon, 2 Nov 2020 15:51:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02C2D206E5 for ; Mon, 2 Nov 2020 15:51:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726488AbgKBPvG (ORCPT ); Mon, 2 Nov 2020 10:51:06 -0500 Received: from foss.arm.com ([217.140.110.172]:32994 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726228AbgKBPvG (ORCPT ); Mon, 2 Nov 2020 10:51:06 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2FFAD30E; Mon, 2 Nov 2020 07:51:05 -0800 (PST) Received: from [192.168.2.22] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 184CB3F719; Mon, 2 Nov 2020 07:51:02 -0800 (PST) From: =?UTF-8?Q?Andr=c3=a9_Przywara?= Subject: Re: [PATCH v6 06/21] perf arm-spe: Refactor printing string to buffer To: Leo Yan , Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , James Clark , Dave Martin , Al Grant , Wei Li , linux-kernel@vger.kernel.org References: <20201030025724.19157-1-leo.yan@linaro.org> <20201030025724.19157-7-leo.yan@linaro.org> Autocrypt: addr=andre.przywara@arm.com; prefer-encrypt=mutual; keydata= xsFNBFNPCKMBEAC+6GVcuP9ri8r+gg2fHZDedOmFRZPtcrMMF2Cx6KrTUT0YEISsqPoJTKld tPfEG0KnRL9CWvftyHseWTnU2Gi7hKNwhRkC0oBL5Er2hhNpoi8x4VcsxQ6bHG5/dA7ctvL6 kYvKAZw4X2Y3GTbAZIOLf+leNPiF9175S8pvqMPi0qu67RWZD5H/uT/TfLpvmmOlRzNiXMBm kGvewkBpL3R2clHquv7pB6KLoY3uvjFhZfEedqSqTwBVu/JVZZO7tvYCJPfyY5JG9+BjPmr+ REe2gS6w/4DJ4D8oMWKoY3r6ZpHx3YS2hWZFUYiCYovPxfj5+bOr78sg3JleEd0OB0yYtzTT esiNlQpCo0oOevwHR+jUiaZevM4xCyt23L2G+euzdRsUZcK/M6qYf41Dy6Afqa+PxgMEiDto ITEH3Dv+zfzwdeqCuNU0VOGrQZs/vrKOUmU/QDlYL7G8OIg5Ekheq4N+Ay+3EYCROXkstQnf YYxRn5F1oeVeqoh1LgGH7YN9H9LeIajwBD8OgiZDVsmb67DdF6EQtklH0ycBcVodG1zTCfqM AavYMfhldNMBg4vaLh0cJ/3ZXZNIyDlV372GmxSJJiidxDm7E1PkgdfCnHk+pD8YeITmSNyb 7qeU08Hqqh4ui8SSeUp7+yie9zBhJB5vVBJoO5D0MikZAODIDwARAQABzS1BbmRyZSBQcnp5 d2FyYSAoQVJNKSA8YW5kcmUucHJ6eXdhcmFAYXJtLmNvbT7CwXsEEwECACUCGwMGCwkIBwMC BhUIAgkKCwQWAgMBAh4BAheABQJTWSV8AhkBAAoJEAL1yD+ydue63REP/1tPqTo/f6StS00g NTUpjgVqxgsPWYWwSLkgkaUZn2z9Edv86BLpqTY8OBQZ19EUwfNehcnvR+Olw+7wxNnatyxo D2FG0paTia1SjxaJ8Nx3e85jy6l7N2AQrTCFCtFN9lp8Pc0LVBpSbjmP+Peh5Mi7gtCBNkpz KShEaJE25a/+rnIrIXzJHrsbC2GwcssAF3bd03iU41J1gMTalB6HCtQUwgqSsbG8MsR/IwHW XruOnVp0GQRJwlw07e9T3PKTLj3LWsAPe0LHm5W1Q+euoCLsZfYwr7phQ19HAxSCu8hzp43u zSw0+sEQsO+9wz2nGDgQCGepCcJR1lygVn2zwRTQKbq7Hjs+IWZ0gN2nDajScuR1RsxTE4WR lj0+Ne6VrAmPiW6QqRhliDO+e82riI75ywSWrJb9TQw0+UkIQ2DlNr0u0TwCUTcQNN6aKnru ouVt3qoRlcD5MuRhLH+ttAcmNITMg7GQ6RQajWrSKuKFrt6iuDbjgO2cnaTrLbNBBKPTG4oF D6kX8Zea0KvVBagBsaC1CDTDQQMxYBPDBSlqYCb/b2x7KHTvTAHUBSsBRL6MKz8wwruDodTM 4E4ToV9URl4aE/msBZ4GLTtEmUHBh4/AYwk6ACYByYKyx5r3PDG0iHnJ8bV0OeyQ9ujfgBBP B2t4oASNnIOeGEEcQ2rjzsFNBFNPCKMBEACm7Xqafb1Dp1nDl06aw/3O9ixWsGMv1Uhfd2B6 it6wh1HDCn9HpekgouR2HLMvdd3Y//GG89irEasjzENZPsK82PS0bvkxxIHRFm0pikF4ljIb 6tca2sxFr/H7CCtWYZjZzPgnOPtnagN0qVVyEM7L5f7KjGb1/o5EDkVR2SVSSjrlmNdTL2Rd zaPqrBoxuR/y/n856deWqS1ZssOpqwKhxT1IVlF6S47CjFJ3+fiHNjkljLfxzDyQXwXCNoZn BKcW9PvAMf6W1DGASoXtsMg4HHzZ5fW+vnjzvWiC4pXrcP7Ivfxx5pB+nGiOfOY+/VSUlW/9 GdzPlOIc1bGyKc6tGREH5lErmeoJZ5k7E9cMJx+xzuDItvnZbf6RuH5fg3QsljQy8jLlr4S6 8YwxlObySJ5K+suPRzZOG2+kq77RJVqAgZXp3Zdvdaov4a5J3H8pxzjj0yZ2JZlndM4X7Msr P5tfxy1WvV4Km6QeFAsjcF5gM+wWl+mf2qrlp3dRwniG1vkLsnQugQ4oNUrx0ahwOSm9p6kM CIiTITo+W7O9KEE9XCb4vV0ejmLlgdDV8ASVUekeTJkmRIBnz0fa4pa1vbtZoi6/LlIdAEEt PY6p3hgkLLtr2GRodOW/Y3vPRd9+rJHq/tLIfwc58ZhQKmRcgrhtlnuTGTmyUqGSiMNfpwAR AQABwsFfBBgBAgAJBQJTTwijAhsMAAoJEAL1yD+ydue64BgP/33QKczgAvSdj9XTC14wZCGE U8ygZwkkyNf021iNMj+o0dpLU48PIhHIMTXlM2aiiZlPWgKVlDRjlYuc9EZqGgbOOuR/pNYA JX9vaqszyE34JzXBL9DBKUuAui8z8GcxRcz49/xtzzP0kH3OQbBIqZWuMRxKEpRptRT0wzBL O31ygf4FRxs68jvPCuZjTGKELIo656/Hmk17cmjoBAJK7JHfqdGkDXk5tneeHCkB411p9WJU vMO2EqsHjobjuFm89hI0pSxlUoiTL0Nuk9Edemjw70W4anGNyaQtBq+qu1RdjUPBvoJec7y/ EXJtoGxq9Y+tmm22xwApSiIOyMwUi9A1iLjQLmngLeUdsHyrEWTbEYHd2sAM2sqKoZRyBDSv ejRvZD6zwkY/9nRqXt02H1quVOP42xlkwOQU6gxm93o/bxd7S5tEA359Sli5gZRaucpNQkwd KLQdCvFdksD270r4jU/rwR2R/Ubi+txfy0dk2wGBjl1xpSf0Lbl/KMR5TQntELfLR4etizLq Xpd2byn96Ivi8C8u9zJruXTueHH8vt7gJ1oax3yKRGU5o2eipCRiKZ0s/T7fvkdq+8beg9ku fDO4SAgJMIl6H5awliCY2zQvLHysS/Wb8QuB09hmhLZ4AifdHyF1J5qeePEhgTA+BaUbiUZf i4aIXCH3Wv6K Organization: ARM Ltd. Message-ID: <91d5de6b-885e-d56d-0845-49b2dde6894c@arm.com> Date: Mon, 2 Nov 2020 15:50:01 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201030025724.19157-7-leo.yan@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/10/2020 02:57, Leo Yan wrote: > When outputs strings to the decoding buffer with function snprintf(), > SPE decoder needs to detects if any error returns from snprintf() and if > so needs to directly bail out. If snprintf() returns success, it needs > to update buffer pointer and reduce the buffer length so can continue to > output the next string into the consequent memory space. > > This complex logics are spreading in the function arm_spe_pkt_desc() so > there has many duplicate codes for handling error detecting, increment > buffer pointer and decrement buffer size. > > To avoid the duplicate code, this patch introduces a new helper function > arm_spe_pkt_snprintf() which is used to wrap up the complex logics, and > it's used by the caller arm_spe_pkt_desc(); if printing buffer is called > for multiple times in a flow, the error is a cumulative value and simply > returns its final value. > > This patch also moves the variable 'blen' as the function's local > variable, this allows to remove the unnecessary braces and improve the > readability. > > Suggested-by: Dave Martin > Signed-off-by: Leo Yan Wow, that's a bit tricky to review in its current incarnation, but it looks alright to me. I have some optimisation idea below, but that's a nit and the patch as is seems correct to me (checked twice, the second time in an editor, matching the lines), so: Reviewed-by: Andre Przywara ... > --- > .../arm-spe-decoder/arm-spe-pkt-decoder.c | 267 ++++++++---------- > 1 file changed, 117 insertions(+), 150 deletions(-) > > diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c > index 04fd7fd7c15f..1ecaf9805b79 100644 > --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c > +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > > #include "arm-spe-pkt-decoder.h" > > @@ -258,192 +259,158 @@ int arm_spe_get_packet(const unsigned char *buf, size_t len, > return ret; > } > > +static int arm_spe_pkt_snprintf(int *err, char **buf_p, size_t *blen, > + const char *fmt, ...) > +{ > + va_list ap; > + int ret; > + > + /* Bail out if any error occurred */ > + if (err && *err) > + return *err; > + > + va_start(ap, fmt); > + ret = vsnprintf(*buf_p, *blen, fmt, ap); > + va_end(ap); > + > + if (ret < 0) { > + if (err && !*err) > + *err = ret; > + } else { > + *buf_p += ret; > + *blen -= ret; > + } > + > + return ret; > +} > + > int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf, > size_t buf_len) > { > - int ret, ns, el, idx = packet->index; > + int ns, el, idx = packet->index; > unsigned long long payload = packet->payload; > const char *name = arm_spe_pkt_name(packet->type); > + size_t blen = buf_len; > + int err = 0; > > switch (packet->type) { > case ARM_SPE_BAD: > case ARM_SPE_PAD: > case ARM_SPE_END: > - return snprintf(buf, buf_len, "%s", name); > - case ARM_SPE_EVENTS: { > - size_t blen = buf_len; > - > - ret = 0; > - ret = snprintf(buf, buf_len, "EV"); > - buf += ret; > - blen -= ret; > - if (payload & 0x1) { > - ret = snprintf(buf, buf_len, " EXCEPTION-GEN"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x2) { > - ret = snprintf(buf, buf_len, " RETIRED"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x4) { > - ret = snprintf(buf, buf_len, " L1D-ACCESS"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x8) { > - ret = snprintf(buf, buf_len, " L1D-REFILL"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x10) { > - ret = snprintf(buf, buf_len, " TLB-ACCESS"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x20) { > - ret = snprintf(buf, buf_len, " TLB-REFILL"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x40) { > - ret = snprintf(buf, buf_len, " NOT-TAKEN"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x80) { > - ret = snprintf(buf, buf_len, " MISPRED"); > - buf += ret; > - blen -= ret; > - } > + return arm_spe_pkt_snprintf(&err, &buf, &blen, "%s", name); Nothing critical, but in case you need to respin this series for whatever reason, you might want to use NULL for the first argument, since you return here and there is little point in setting err. Same for other cases where you return directly from an arm_spe_pkt_snprintf() call. But it doesn't hurt, so you could leave it as well, and it's more robust in case someone extends the code later. > + case ARM_SPE_EVENTS: > + arm_spe_pkt_snprintf(&err, &buf, &blen, "EV"); > + > + if (payload & 0x1) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " EXCEPTION-GEN"); > + if (payload & 0x2) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " RETIRED"); > + if (payload & 0x4) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " L1D-ACCESS"); > + if (payload & 0x8) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " L1D-REFILL"); > + if (payload & 0x10) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " TLB-ACCESS"); > + if (payload & 0x20) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " TLB-REFILL"); > + if (payload & 0x40) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " NOT-TAKEN"); > + if (payload & 0x80) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " MISPRED"); > if (idx > 1) { > - if (payload & 0x100) { > - ret = snprintf(buf, buf_len, " LLC-ACCESS"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x200) { > - ret = snprintf(buf, buf_len, " LLC-REFILL"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x400) { > - ret = snprintf(buf, buf_len, " REMOTE-ACCESS"); > - buf += ret; > - blen -= ret; > - } > + if (payload & 0x100) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " LLC-ACCESS"); > + if (payload & 0x200) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " LLC-REFILL"); > + if (payload & 0x400) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " REMOTE-ACCESS"); > } > - if (ret < 0) > - return ret; > - blen -= ret; > - return buf_len - blen; > - } > + return err ?: (int)(buf_len - blen); > + > case ARM_SPE_OP_TYPE: > switch (idx) { > - case 0: return snprintf(buf, buf_len, "%s", payload & 0x1 ? > - "COND-SELECT" : "INSN-OTHER"); > - case 1: { > - size_t blen = buf_len; > + case 0: > + return arm_spe_pkt_snprintf(&err, &buf, &blen, > + payload & 0x1 ? "COND-SELECT" : "INSN-OTHER"); same here (and below, you get the idea ...) Cheers, Andre > + case 1: > + arm_spe_pkt_snprintf(&err, &buf, &blen, > + payload & 0x1 ? "ST" : "LD"); > > - if (payload & 0x1) > - ret = snprintf(buf, buf_len, "ST"); > - else > - ret = snprintf(buf, buf_len, "LD"); > - buf += ret; > - blen -= ret; > if (payload & 0x2) { > - if (payload & 0x4) { > - ret = snprintf(buf, buf_len, " AT"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x8) { > - ret = snprintf(buf, buf_len, " EXCL"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x10) { > - ret = snprintf(buf, buf_len, " AR"); > - buf += ret; > - blen -= ret; > - } > + if (payload & 0x4) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " AT"); > + if (payload & 0x8) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " EXCL"); > + if (payload & 0x10) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " AR"); > } else if (payload & 0x4) { > - ret = snprintf(buf, buf_len, " SIMD-FP"); > - buf += ret; > - blen -= ret; > - } > - if (ret < 0) > - return ret; > - blen -= ret; > - return buf_len - blen; > - } > - case 2: { > - size_t blen = buf_len; > - > - ret = snprintf(buf, buf_len, "B"); > - buf += ret; > - blen -= ret; > - if (payload & 0x1) { > - ret = snprintf(buf, buf_len, " COND"); > - buf += ret; > - blen -= ret; > - } > - if (payload & 0x2) { > - ret = snprintf(buf, buf_len, " IND"); > - buf += ret; > - blen -= ret; > + arm_spe_pkt_snprintf(&err, &buf, &blen, " SIMD-FP"); > } > - if (ret < 0) > - return ret; > - blen -= ret; > - return buf_len - blen; > - } > - default: return 0; > + > + return err ?: (int)(buf_len - blen); > + > + case 2: > + arm_spe_pkt_snprintf(&err, &buf, &blen, "B"); > + > + if (payload & 0x1) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " COND"); > + if (payload & 0x2) > + arm_spe_pkt_snprintf(&err, &buf, &blen, " IND"); > + > + return err ?: (int)(buf_len - blen); > + > + default: > + return 0; > } > case ARM_SPE_DATA_SOURCE: > case ARM_SPE_TIMESTAMP: > - return snprintf(buf, buf_len, "%s %lld", name, payload); > + return arm_spe_pkt_snprintf(&err, &buf, &blen, "%s %lld", name, payload); > case ARM_SPE_ADDRESS: > switch (idx) { > case 0: > case 1: ns = !!(packet->payload & NS_FLAG); > el = (packet->payload & EL_FLAG) >> 61; > payload &= ~(0xffULL << 56); > - return snprintf(buf, buf_len, "%s 0x%llx el%d ns=%d", > + return arm_spe_pkt_snprintf(&err, &buf, &blen, > + "%s 0x%llx el%d ns=%d", > (idx == 1) ? "TGT" : "PC", payload, el, ns); > - case 2: return snprintf(buf, buf_len, "VA 0x%llx", payload); > + case 2: > + return arm_spe_pkt_snprintf(&err, &buf, &blen, > + "VA 0x%llx", payload); > case 3: ns = !!(packet->payload & NS_FLAG); > payload &= ~(0xffULL << 56); > - return snprintf(buf, buf_len, "PA 0x%llx ns=%d", > - payload, ns); > - default: return 0; > + return arm_spe_pkt_snprintf(&err, &buf, &blen, > + "PA 0x%llx ns=%d", payload, ns); > + default: > + return 0; > } > case ARM_SPE_CONTEXT: > - return snprintf(buf, buf_len, "%s 0x%lx el%d", name, > - (unsigned long)payload, idx + 1); > - case ARM_SPE_COUNTER: { > - size_t blen = buf_len; > - > - ret = snprintf(buf, buf_len, "%s %d ", name, > - (unsigned short)payload); > - buf += ret; > - blen -= ret; > + return arm_spe_pkt_snprintf(&err, &buf, &blen, "%s 0x%lx el%d", > + name, (unsigned long)payload, idx + 1); > + case ARM_SPE_COUNTER: > + arm_spe_pkt_snprintf(&err, &buf, &blen, "%s %d ", name, > + (unsigned short)payload); > + > switch (idx) { > - case 0: ret = snprintf(buf, buf_len, "TOT"); break; > - case 1: ret = snprintf(buf, buf_len, "ISSUE"); break; > - case 2: ret = snprintf(buf, buf_len, "XLAT"); break; > - default: ret = 0; > + case 0: > + arm_spe_pkt_snprintf(&err, &buf, &blen, "TOT"); > + break; > + case 1: > + arm_spe_pkt_snprintf(&err, &buf, &blen, "ISSUE"); > + break; > + case 2: > + arm_spe_pkt_snprintf(&err, &buf, &blen, "XLAT"); > + break; > + default: > + break; > } > - if (ret < 0) > - return ret; > - blen -= ret; > - return buf_len - blen; > - } > + > + return err ?: (int)(buf_len - blen); > + > default: > break; > } > > - return snprintf(buf, buf_len, "%s 0x%llx (%d)", > - name, payload, packet->index); > + return arm_spe_pkt_snprintf(&err, &buf, &blen, "%s 0x%llx (%d)", > + name, payload, packet->index); > } >