Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0eeb06b9 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

utils: Add FastStrcmp.h 

Move existing fast<str*cmp> templates for general use, pulled from
the implementation used in logd that dealt with speed through cache
locality and subroutine call mitigation.  Rename to fastcmp.

Test: logd-benchmarks and based on manual profiling from the past
Bug: 31456426
Change-Id: Ic62f4a437fc3e06ffdeaae73a6f34e197957a6b0
parent aece4251

include/utils/FastStrcmp.h

0 → 100644
+54 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2014-2016 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */



#ifndef _ANDROID_UTILS_FASTSTRCMP_H__

#define _ANDROID_UTILS_FASTSTRCMP_H__



#ifdef __cplusplus



// Optimized for instruction cache locality

//

// Template class fastcmp used to create more time-efficient str*cmp

// functions by pre-checking the first character before resorting

// to calling the underlying string function.  Profiled with a

// measurable speedup when used in hot code.  Usage is of the form:

//

//  fastcmp<strncmp>(str1, str2, len)

//

// NB: Does not work for the case insensitive str*cmp functions.

// NB: Returns boolean, do not use if expecting to check negative value.

//     Thus not semantically identical to the expected function behavior.



template <int (*cmp)(const char *l, const char *r, const size_t s)>

static inline int fastcmp(const char *l, const char *r, const size_t s) {

    return (*l != *r) || cmp(l + 1, r + 1, s - 1);

}



template <int (*cmp)(const void *l, const void *r, const size_t s)>

static inline int fastcmp(const void *lv, const void *rv, const size_t s) {

    const char *l = static_cast<const char *>(lv);

    const char *r = static_cast<const char *>(rv);

    return (*l != *r) || cmp(l + 1, r + 1, s - 1);

}



template <int (*cmp)(const char *l, const char *r)>

static inline int fastcmp(const char *l, const char *r) {

    return (*l != *r) || cmp(l + 1, r + 1);

}



#endif



#endif // _ANDROID_UTILS_FASTSTRCMP_H__

logd/LogBufferElement.cpp

+1 −1
Original line number Diff line number Diff line
@@ -89,7 +89,7 @@ char *android::tidToName(pid_t tid) { 
        size_t name_len = strlen(name);

        // KISS: ToDo: Only checks prefix truncated, not suffix, or both

        if ((retval_len < name_len)

                && !fast<strcmp>(retval, name + name_len - retval_len)) {

                && !fastcmp<strcmp>(retval, name + name_len - retval_len)) {

            free(retval);

            retval = name;

        } else {

logd/LogKlog.cpp

+10 −10
Original line number Diff line number Diff line
@@ -321,7 +321,7 @@ static const char *strnstr(const char *s, size_t len, const char *needle) { 
                }

                --len;

            } while (*s++ != c);

        } while (fast<memcmp>(s, needle, needleLen));

        } while (fastcmp<memcmp>(s, needle, needleLen));

        s--;

    }

    return s;
@@ -640,7 +640,7 @@ int LogKlog::log(const char *buf, size_t len) { 


    static const char infoBrace[] = "[INFO]";

    static const size_t infoBraceLen = strlen(infoBrace);

    if ((taglen >= infoBraceLen) && !fast<strncmp>(p, infoBrace, infoBraceLen)) {

    if ((taglen >= infoBraceLen) && !fastcmp<strncmp>(p, infoBrace, infoBraceLen)) {

        // <PRI>[<TIME>] "[INFO]"<tag> ":" message

        bt = p + infoBraceLen;

        taglen -= infoBraceLen;
@@ -675,7 +675,7 @@ int LogKlog::log(const char *buf, size_t len) { 
            p = cp + 1;

        } else if ((taglen > size) && (tolower(*bt) == tolower(*cp))) {

            // clean up any tag stutter

            if (!fast<strncasecmp>(bt + 1, cp + 1, size - 1)) { // no match

            if (!fastcmp<strncasecmp>(bt + 1, cp + 1, size - 1)) { // no match

                // <PRI>[<TIME>] <tag> <tag> : message

                // <PRI>[<TIME>] <tag> <tag>: message

                // <PRI>[<TIME>] <tag> '<tag>.<num>' : message
@@ -697,8 +697,8 @@ int LogKlog::log(const char *buf, size_t len) { 
                static const char host[] = "_host";

                static const size_t hostlen = strlen(host);

                if ((size > hostlen) &&

                        !fast<strncmp>(bt + size - hostlen, host, hostlen) &&

                        !fast<strncmp>(bt + 1, cp + 1, size - hostlen - 1)) {

                        !fastcmp<strncmp>(bt + size - hostlen, host, hostlen) &&

                        !fastcmp<strncmp>(bt + 1, cp + 1, size - hostlen - 1)) {

                    const char *b = cp;

                    cp += size - hostlen;

                    taglen -= size - hostlen;
@@ -746,10 +746,10 @@ twoWord: while (--taglen && !isspace(*++cp) && (*cp != ':')); 
        // register names like x18 but not driver names like en0

            || ((size == 3) && (isdigit(tag[1]) && isdigit(tag[2])))

        // blacklist

            || ((size == cpuLen) && !fast<strncmp>(tag, cpu, cpuLen))

            || ((size == warningLen) && !fast<strncasecmp>(tag, warning, warningLen))

            || ((size == errorLen) && !fast<strncasecmp>(tag, error, errorLen))

            || ((size == infoLen) && !fast<strncasecmp>(tag, info, infoLen))) {

            || ((size == cpuLen) && !fastcmp<strncmp>(tag, cpu, cpuLen))

            || ((size == warningLen) && !fastcmp<strncasecmp>(tag, warning, warningLen))

            || ((size == errorLen) && !fastcmp<strncasecmp>(tag, error, errorLen))

            || ((size == infoLen) && !fastcmp<strncasecmp>(tag, info, infoLen))) {

        p = start;

        etag = tag = "";

    }
@@ -761,7 +761,7 @@ twoWord: while (--taglen && !isspace(*++cp) && (*cp != ':')); 
    const char *mp = strnrchr(tag, ']', taglen);

    if (mp && (++mp < etag)) {

        size_t s = etag - mp;

        if (((s + s) < taglen) && !fast<memcmp>(mp, mp - 1 - s, s)) {

        if (((s + s) < taglen) && !fastcmp<memcmp>(mp, mp - 1 - s, s)) {

            taglen = mp - tag;

        }

    }

logd/LogReader.cpp

+1 −1
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ bool LogReader::onDataAvailable(SocketClient *cli) { 
    }



    bool nonBlock = false;

    if (!fast<strncmp>(buffer, "dumpAndClose", 12)) {

    if (!fastcmp<strncmp>(buffer, "dumpAndClose", 12)) {

        // Allow writer to get some cycles, and wait for pending notifications

        sched_yield();

        LogTimeEntry::lock();

logd/LogStatistics.cpp

+2 −2
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ char *pidToName(pid_t pid) { 
            if (ret > 0) {

                buffer[sizeof(buffer)-1] = '\0';

                // frameworks intermediate state

                if (fast<strcmp>(buffer, "<pre-initialized>")) {

                if (fastcmp<strcmp>(buffer, "<pre-initialized>")) {

                    retval = strdup(buffer);

                }

            }
@@ -209,7 +209,7 @@ const char *LogStatistics::uidToName(uid_t uid) const { 
            if (nameTmp) {

                if (!name) {

                    name = strdup(nameTmp);

                } else if (fast<strcmp>(name, nameTmp)) {

                } else if (fastcmp<strcmp>(name, nameTmp)) {

                    free(const_cast<char *>(name));

                    name = NULL;

                    break;