intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

6 files changed, 831 insertions, 0 deletions

diff --git a/library/cpp/execprofile/annotate_profile.pl b/library/cpp/execprofile/annotate_profile.pl
new file mode 100644
index 00000000000..1a8c5d65a15
--- /dev/null
+++ b/library/cpp/execprofile/annotate_profile.pl
@@ -0,0 +1,360 @@
+#!/usr/bin/env perl
+
+#
+# Takes profile file as an input and prints out annotated disassmebly
+# Usage:
+#    ./annotate_profile.pl <binary_name> <profile_name>
+#
+
+
+# Function to draw bar of the specified length filled up to specified length
+sub DRAW_BAR($$) {
+    my ($length, $filled) = @_;
+    my $bar = "";
+    --$filled;
+    while ($filled > 0) {
+        $bar = $bar . "X";
+        $length--;
+        $filled--;
+    }
+    while ($length > 0) {
+        $bar = $bar . " ";
+        $length--;
+    }
+    return $bar;
+}
+
+my $curFunc = "";
+my $curModule = "";
+my $allHits = 0;
+my %moduleHits;
+my %funcModule;
+my %funcHits;
+my %funcHottestCount;
+my %funcStart;
+my %funcEnd;
+my %funcNames;
+my %funcBaseAddrs;
+my %funcSizes;
+my %addrHits;
+my %addrFunc;
+my %moduleBaseAddr;
+my @funcSortByAddr;
+my %demangledNames;
+my %srcLineHits;
+my %srcFileHits;
+
+# Demagles C++ function name
+sub DEMANGLE($) {
+    my ($name) = @_;
+    if (exists $demangledNames{$name}) {
+        return $demangledNames{$name};
+    }
+    if ($name =~ /^_Z/) {
+        my $cmd = "c++filt -p \'$name\' |";
+        open(my $RES, $cmd ) || die "No c++filt";
+        my $demangled_name = <$RES>;
+        chomp($demangled_name);
+        close $RES;
+        if (length($demangled_name) !=0) {
+            $name = $demangled_name;
+        }
+    }
+    return $name;
+}
+
+# Saves function info
+sub AddFunc($$$$$)
+{
+    my ($func, $bin_file, $baseAddr, $size, $name) = @_;
+    $funcModule{$func} = $bin_file;
+    $funcBaseAddrs{$func} = $baseAddr;
+    # A function with the same base address can be mentioned multiple times with different sizes (0, and non-0, WTF??)
+    if ((! exists $funcSizes{$func}) || ($funcSizes{$func} < $size)) {
+        $funcSizes{$func} = $size;
+    }
+    $funcNames{$func} = $name;
+    $funcStart{$func} = $func;
+#    printf "%08x\t%08x\t%016x\t%s\t%s\n",
+#        $funcBaseAddrs{$func}, $funcSizes{$func}, $moduleBaseAddr, $funcModule{$func}, $funcNames{$func};
+}
+
+# Reads list of all functions in a module
+sub ReadFunctionList($$) {
+    my ($bin_file, $moduleBaseAddr) = @_;
+    if (! -e $bin_file) {
+        return;
+    }
+    my $readelf_cmd = "readelf -W -s $bin_file |";
+#    print "$readelf_cmd\n";
+    my $IN_FILE;
+    open($IN_FILE, $readelf_cmd) || die "couldn't open the file!";
+    while (my $line = <$IN_FILE>) {
+        chomp($line);
+        # "    33: 00000000000a0fc0   433 FUNC    GLOBAL DEFAULT   10 getipnodebyaddr@@FBSD_1.0"
+        if ($line =~ m/^\s*\d+:\s+([0-9a-fA-F]+)\s+(\d+)\s+FUNC\s+\w+\s+DEFAULT\s+\d+\s+(.*)$/) {
+            # Read function info
+            my $name = $3;
+            my $baseAddr = hex($1) + $moduleBaseAddr;
+            my $func = $baseAddr;
+            my $size = $2;
+            AddFunc($func, $bin_file, $baseAddr, $size, $name);
+        }
+    }
+    close($IN_FILE);
+    @funcSortByAddr = sort {$funcBaseAddrs{$a} <=> $funcBaseAddrs{$b} } keys %funcBaseAddrs;
+#    printf "%016x\t%s\t%d\n", $moduleBaseAddr, $bin_file, $#funcSortByAddr+1;
+}
+
+# Reads the profile and attributes address hits to the functions
+sub ReadSamples() {
+    # First pass saves all samples in a hash-table
+    my $samples_file = $ARGV[1];
+    my $IN_FILE;
+    open($IN_FILE, $samples_file)|| die "couldn't open the file!";
+    my $curFuncInd = 0;
+    my $curFunc = 0;
+    my $curFuncBegin = 0;
+    my $curFuncEnd = 0;
+    my $curModule = "";
+    my $curModuleBase = 0;
+    my $read_samples = 0;
+    my $samplesStarted = 0;
+    while (my $line = <$IN_FILE>) {
+        chomp($line);
+
+        if ($line =~ m/^samples:\s+(\d+)\s+unique:\s+(\d+)\s+dropped:\s+(\d+)\s+searchskips:\s+(\d+)$/) {
+            $total_samples = $1;
+            $unique_samples = $2;
+            $dropped_samples = $3;
+            $search_skips = $4;
+            next;
+        }
+
+        if ($line =~ m/^Samples:$/) {
+            $samplesStarted = 1;
+            next;
+        } elsif (!$samplesStarted) {
+            print "$line\n";
+            next;
+        }
+
+#        print "$line\n";
+        if  ($line =~ m/^Func\t\d+/) {
+            # "Func 2073  0x803323000 0x803332fd0 /lib/libthr.so.3 pthread_cond_init"
+            my @cols = split(/\t/, $line);
+            $curModule = $cols[4];
+            $curModuleBase = hex($cols[2]);
+            if (0x400000 == $curModuleBase) {
+                $curModuleBase = 0;
+            }
+            $curFunc = hex($cols[3]);
+            if (! exists $moduleBaseAddr{$curModule}) {
+                $moduleBaseAddr{$curModule} = $curModuleBase;
+                ReadFunctionList($curModule, $curModuleBase);
+            }
+            if (! exists $funcNames{$curFunc}) {
+                my $name = sprintf("unknown_0x%08x", $curFunc);
+                AddFunc($curFunc, $curModule, $curFunc, 0, $name);
+            }
+        } elsif ($line =~ m/^\d+\t0x([0-9,a-f,A-F]+)\t(\d+)/) {
+            # Read one sample for the current function
+            $read_samples++;
+            my $addr = hex($1);
+#            print "$addr\n";
+            if ($addr >= $curFuncEnd) {
+                # Find the function the current address belongs to
+                while ($curFuncInd <= $#funcSortByAddr) {
+                    my $f = $funcSortByAddr[$curFuncInd];
+                    my $begin = $funcBaseAddrs{$f};
+                    my $end = $funcBaseAddrs{$f} + $funcSizes{$f};
+                    if ($begin <= $addr and $addr < $end) {
+                        $curFunc = $f;
+                        $funcStart{$curFunc} = $addr;
+                        $curFuncBegin = $begin;
+                        $curFuncEnd = $end;
+                        last;
+                    } elsif ($addr < $begin) {
+#                        printf "X3: func:%08x\tname:%s\tbase:%08x\tsize:%08x\t%s\nline:%s\n",
+#                            $curFunc, $funcNames{$curFunc}, $funcBaseAddrs{$curFunc}, $funcSizes{$curFunc}, $curModule, $line;
+                        last;
+                    }
+                    ++$curFuncInd;
+                }
+            }
+
+            $funcHits{$curFunc} += $2;
+            if ($funcHottestCount{$curFunc} < $2) {
+                $funcHottestCount{$curFunc} = $2;
+            }
+            $addrHits{$addr} = $2;
+            $addrFunc{$addr} = $curFunc;
+            $funcEnd{$curFunc} = $addr;
+            $allHits += $2;
+	    $moduleHits{$curModule} += $2;
+
+#    	    printf "%08x\t%08x\t%08x\t%08x\t%s\n", $addr, $curFunc, $curFuncBegin, $curFuncEnd, $funcNames{$curFunc};
+        }
+    }
+    close($IN_FILE);
+    
+    printf "\nsamples: %d    unique: %d   dropped: %d   searchskips: %d\n",  $total_samples, $unique_samples, $dropped_samples, $search_skips;
+    if ($read_samples != $unique_samples) {
+        printf "\n-----------------------------------------------------------------------------------------------------\n";
+        printf "!!!!WARNING: read %d samples, expected %d samples, profiling results might be not acqurate!!!!", $read_samples, $unique_samples;
+        printf "\n-----------------------------------------------------------------------------------------------------\n";
+    }
+}
+
+# Dumps module stats
+sub DumpModules() {
+    # Sort functions by hit counts and dump the list
+    my @modules = sort {$a <=> $b } keys %moduleHits;
+    for (my $i = 0; $i <= $#modules; ++$i) {
+        my $m = $modules[$i];
+        my $cnt = $moduleHits{$m};
+        my $perc = 100.0 * $cnt / $allHits;
+        printf "%12d\t%6.2f%% |%s  %s\n", $cnt, $perc, DRAW_BAR(20, 20*$cnt/$allHits), $m;
+    }
+}
+
+# Dumps top N hot functions
+sub DumpHotFunc($) {
+    my ($maxCnt) = @_;
+    # Sort functions by hit counts and dump the list
+    my @hotFunc = sort {$funcHits{$b} <=> $funcHits{$a} } keys %funcHits;
+#    print $#hotFunc;
+    for (my $i = 0; $i <= $#hotFunc && $i < $maxCnt; ++$i) {
+        my $f = $hotFunc[$i];
+        my $cnt = $funcHits{$f};
+        my $perc = 100.0 * $cnt / $allHits;
+        printf "%12d\t%6.2f%% |%s  %s\n", $cnt, $perc, DRAW_BAR(20, 20*$cnt/$allHits), DEMANGLE($funcNames{$f});
+    }
+}
+
+# Dumps top N hotspots (hot addresses)
+sub DumpHotSpots($) {
+    my ($maxCnt) = @_;
+    # Sort addresses by hit counts and dump the list
+    my @hotSpots = sort {$addrHits{$b} <=> $addrHits{$a} } keys %addrHits;
+    for (my $i = 0; $i <= $#hotSpots && $i < $maxCnt; ++$i) {
+        my $s = $hotSpots[$i];
+        my $cnt = $addrHits{$s};
+        my $perc = 100.0 * $cnt / $allHits;
+        my $f = $addrFunc{$s};
+        my $fname = $funcNames{$f};
+        printf "%12d\t%6.2f%% |%s  0x%016x\t%s + 0x%x\n",
+            $cnt, $perc, DRAW_BAR(20, 20*$cnt/$allHits), $s, DEMANGLE($fname), $s - $funcBaseAddrs{$f};
+    }
+}
+
+# Adds hit informations to a disassembly line
+sub ANNOTATE_DISASSM($$$$) {
+    my ($address, $disassm, $max_hit_count, $func_hit_count) = @_;
+    my $hit_count = $addrHits{$address};
+    my $perc = sprintf("% 7.2f%%", 100*$hit_count/$func_hit_count);
+    $address = sprintf("% 8x", $address);
+    print $address . " " . $hit_count . "\t" . $perc . " |" .
+        DRAW_BAR(20, 20*$hit_count/$max_hit_count) . "\t" . $disassm . "\n";
+}
+
+# Dumps annotated disassembly of the specified function (actually not the whole function but
+# just the addresses between the first and last hit)
+sub DumpDisasm($) {
+    my ($name) = @_;
+    if (exists $funcStart{$name} && exists $funcEnd{$name} && $funcStart{$name}!=0) {
+        my $module = $funcModule{$name};
+        my $modBase = $moduleBaseAddr{$module};
+        my $start_address = $funcStart{$name} - $modBase;
+        my $stop_address = $funcEnd{$name} - $modBase + 1;
+#        print " " . $funcStart{$name} . " " . $funcEnd{$name} . " $modBase ---";
+        my $max_hit_count = $funcHits{$name};
+        my $objdump_cmd = "objdump -C -d -l --start-address=" . $start_address .
+            " --stop-address=" . $stop_address . " " . $module . " |";
+        if ($stop_address - $start_address < 10000000) { # don't try to disaassemble more than 10MB, because most likely it's a bug
+#        print STDERR $objdump_cmd . "\n";
+        open(my $OBJDUMP, $objdump_cmd) || die "No objdump";
+        my $srcLine = "func# ". $name;
+        my $srcFile = $module;
+        while (my $objdump_line = <$OBJDUMP>) {
+            # filter disassembly lines
+            if ($objdump_line =~ /^Disassembly of section/) {
+            } elsif ($objdump_line =~ m/^\s*([0-9,a-f,A-F]+):\s*(.*)/) {
+                my $addr = hex($1);
+                my $hit_count = $addrHits{$addr};
+                if ($hit_count > 0) {
+                    $srcLineHits{$srcLine} += $hit_count;
+                    $srcFileHits{$srcFile} += $hit_count;
+                }
+                ANNOTATE_DISASSM($addr + $modBase, $2, $funcHottestCount{$name}, $max_hit_count);
+            } elsif ($objdump_line =~ m/^(\/.*):(\d+)$/) {
+                $srcLine = $objdump_line;
+                $srcFile = $1;
+                chomp($srcLine);
+                print $objdump_line;
+            } else {
+                print $objdump_line;
+            }
+        }
+        close $OBJDUMP;
+        }
+    }
+}
+
+# Dumps disassemlby for top N hot functions
+sub DumpFuncDissasm($) {
+    (my $maxCnt) = @_;
+    my @funcs = sort {$funcHits{$b} <=> $funcHits{$a} } keys %funcHits;
+    print $#funcs . "\n";
+    for (my $i = 0; $i <= $#funcs && $i < $maxCnt; ++$i) {
+        my $f = $funcs[$i];
+        print "\n--------------------------------------------------------------------------------------------------------------\n";
+        printf "hits:%d\t%7.2f%%\tbase:%08x\tstart:%08x\tend:%08x\t%s\n",
+            $funcHits{$f}, 100*$funcHits{$f}/$allHits, $funcBaseAddrs{$f}, $funcStart{$f}, $funcEnd{$f}, DEMANGLE($funcNames{$f});
+        print "--------------------------------------------------------------------------------------------------------------\n";
+        DumpDisasm($f);
+    }
+}
+
+sub DumpSrcFiles($) {
+    (my $maxCnt) = @_;
+    my @srcFiles = sort {$srcFileHits{$b} <=> $srcFileHits{$a} } keys %srcFileHits;
+    for (my $i = 0; $i <= $#srcFiles && $i < $maxCnt; ++$i) {
+        my $f = $srcFiles[$i];
+        my $cnt = $srcFileHits{$f};
+        printf "%12d\t%6.2f%% |%s %s\n", $cnt, 100*$cnt/$allHits, DRAW_BAR(20, 20*$cnt/$allHits), $f;
+    }
+}
+
+sub DumpSrcLines($) {
+    (my $maxCnt) = @_;
+    my @srcLines = sort {$srcLineHits{$b} <=> $srcLineHits{$a} } keys %srcLineHits;
+    for (my $i = 0; $i <= $#srcLines && $i < $maxCnt; ++$i) {
+        my $l = $srcLines[$i];
+        my $cnt = $srcLineHits{$l};
+        printf "%12d\t%6.2f%% |%s %s\n", $cnt, 100*$cnt/$allHits, DRAW_BAR(20, 20*$cnt/$allHits), $l;
+    }
+}
+
+ReadFunctionList($ARGV[0], 0);
+ReadSamples();
+print "\nModules:\n";
+DumpModules();
+print "\nHot functions:\n";
+DumpHotFunc(100);
+print "\nHotspots:\n";
+DumpHotSpots(100);
+DumpFuncDissasm(100);
+print "\nHot src files:\n";
+DumpSrcFiles(100);
+print "\nHot src lines:\n";
+DumpSrcLines(100);
+
+# my @funcs = sort {$funcBaseAddrs{$a} <=> $funcBaseAddrs{$b} } keys %funcHits;
+#    printf "%d\n", $#funcs;
+#    for (my $i = 0; $i <= $#funcs; ++$i) {
+#        my $f = $funcs[$i];
+#        printf "%s\t%d\tbase:%08x\tstart:%08x\tend:%08x\t%s\n",
+#            $funcNames{$f}, $funcHits{$f}, $funcBaseAddrs{$f}, $funcStart{$f}, $funcEnd{$f}, $funcModule{$f};
+#        #DumpDisasm($f);
+#    }
diff --git a/library/cpp/execprofile/autostart/start.cpp b/library/cpp/execprofile/autostart/start.cpp
new file mode 100644
index 00000000000..4fffb03ae1c
--- /dev/null
+++ b/library/cpp/execprofile/autostart/start.cpp
@@ -0,0 +1,15 @@
+#include <library/cpp/execprofile/profile.h>
+
+namespace {
+    struct TInit {
+        inline TInit() {
+            BeginProfiling();
+        }
+
+        inline ~TInit() {
+            EndProfiling();
+        }
+    };
+
+    const TInit initer;
+}
diff --git a/library/cpp/execprofile/autostart/ya.make b/library/cpp/execprofile/autostart/ya.make
new file mode 100644
index 00000000000..a5b61f075f9
--- /dev/null
+++ b/library/cpp/execprofile/autostart/ya.make
@@ -0,0 +1,13 @@
+LIBRARY()
+
+OWNER(pg)
+
+PEERDIR(
+    library/cpp/execprofile
+)
+
+SRCS(
+    GLOBAL start.cpp
+)
+
+END()
diff --git a/library/cpp/execprofile/profile.cpp b/library/cpp/execprofile/profile.cpp
new file mode 100644
index 00000000000..d05de20203f
--- /dev/null
+++ b/library/cpp/execprofile/profile.cpp
@@ -0,0 +1,417 @@
+#include <util/system/defaults.h>
+
+#include "profile.h"
+
+#if defined(_unix_) && !defined(_bionic_) && !defined(_cygwin_)
+
+#include <signal.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#if defined(_darwin_)
+#include <sys/ucontext.h>
+#else
+#include <ucontext.h>
+#endif
+#include <dlfcn.h>
+
+#include <util/system/platform.h>
+#include <util/generic/hash.h>
+#include <util/generic/map.h>
+#include <util/generic/noncopyable.h>
+#include <util/generic/algorithm.h>
+#include <util/generic/vector.h>
+#include <util/stream/file.h>
+#include <util/string/util.h>
+#include <util/system/datetime.h>
+
+// This class sets SIGPROF handler and captures instruction pointer in it.
+class TExecutionSampler : TNonCopyable {
+public:
+    typedef TVector<std::pair<void*, size_t>> TSampleVector;
+
+    struct TStats {
+        ui64 SavedSamples;
+        ui64 DroppedSamples;
+        ui64 SearchSkipCount;
+    };
+
+    // NOTE: There is no synchronization here as the instance is supposed to be
+    // created on the main thread.
+    static TExecutionSampler* Instance() {
+        if (SInstance == nullptr) {
+            SInstance = new TExecutionSampler();
+        }
+
+        return SInstance;
+    }
+
+    void Start() {
+        // Set signal handler
+        struct sigaction sa;
+        sa.sa_sigaction = ProfilerSignalHandler;
+        sigemptyset(&sa.sa_mask);
+        sa.sa_flags = SA_SIGINFO;
+        if (sigaction(SIGPROF, &sa, &OldSignalHandler) != 0)
+            return;
+
+        // Set interval timer
+        itimerval tv;
+        tv.it_interval.tv_sec = tv.it_value.tv_sec = 0;
+        tv.it_interval.tv_usec = tv.it_value.tv_usec = SAMPLE_INTERVAL;
+        setitimer(ITIMER_PROF, &tv, &OldTimerValue);
+
+        Started = true;
+    }
+
+    void Stop(TSampleVector& sampleVector, TStats& stats) {
+        // Reset signal handler and timer
+        if (Started) {
+            setitimer(ITIMER_PROF, &OldTimerValue, nullptr);
+            sleep(1);
+        }
+
+        WaitForWriteFlag();
+
+        if (Started) {
+            sigaction(SIGPROF, &OldSignalHandler, nullptr);
+            Started = false;
+        }
+
+        TExecutionSampler::TSampleVector hits;
+        hits.reserve(Samples);
+        for (size_t i = 0; i < SZ; ++i) {
+            if (Ips[i].first != nullptr) {
+                hits.push_back(Ips[i]);
+            }
+        }
+        stats.SavedSamples = Samples;
+        stats.DroppedSamples = AtomicGet(DroppedSamples);
+        stats.SearchSkipCount = SearchSkipCount;
+        AtomicUnlock(&WriteFlag);
+
+        Sort(hits.begin(), hits.end(), TCompareFirst());
+
+        sampleVector.swap(hits);
+    }
+
+    void ResetStats() {
+        WaitForWriteFlag();
+        Clear();
+        AtomicUnlock(&WriteFlag);
+    }
+
+private:
+    static const size_t SZ = 2 * 1024 * 1024; // size of the hash table
+                                              // inserts work faster if it's a power of 2
+    static const int SAMPLE_INTERVAL = 1000;  // in microseconds
+
+    struct TCompareFirst {
+        bool operator()(const std::pair<void*, size_t>& a, const std::pair<void*, size_t>& b) const {
+            return a.first < b.first;
+        }
+    };
+
+    TExecutionSampler()
+        : Started(false)
+        , Ips(SZ)
+        , WriteFlag(0)
+        , DroppedSamples(0)
+        , Samples(0)
+        , UniqueSamples(0)
+        , SearchSkipCount(0)
+    {
+    }
+
+    ~TExecutionSampler() = default;
+
+    // Signal handler is not allowed to do anything that can deadlock with activity
+    // on the thread to which the signal is delivered or corrupt data structures that
+    // were in process of update.
+    // One such thing is memory allocation. That's why a fixed size vector is
+    // preallocated at start.
+    static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
+        (void)info;
+        if (signal != SIGPROF) {
+            return;
+        }
+
+        ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
+        Y_ASSERT(SInstance != nullptr);
+
+        SInstance->CaptureIP(GetIp(&ucontext->uc_mcontext));
+    }
+
+    void WaitForWriteFlag() {
+        // Wait for write flag to be reset
+        ui32 delay = 100;
+        while (!AtomicTryLock(&WriteFlag)) {
+            usleep(delay);
+            delay += delay;
+            delay = Min(delay, (ui32)5000);
+        }
+    }
+
+    void CaptureIP(void* rip) {
+        // Check if the handler on another thread is in the process of adding a sample
+        // If this is the case, we just drop the current sample as this should happen
+        // rarely.
+        if (AtomicTryLock(&WriteFlag)) {
+            AddSample(rip);
+            AtomicUnlock(&WriteFlag);
+        } else {
+            AtomicIncrement(DroppedSamples);
+        }
+    }
+
+    // Hash function applied to the addresses
+    static inline ui32 Hash(void* key) {
+        return ((size_t)key + (size_t)key / SZ) % SZ;
+    }
+
+    // Get instruction pointer from the context
+    static inline void* GetIp(const mcontext_t* mctx) {
+#if defined _freebsd_
+#if defined _64_
+        return (void*)mctx->mc_rip;
+#else
+        return (void*)mctx->mc_eip;
+#endif
+#elif defined _linux_
+#if defined _64_
+#if defined(_arm_)
+        return (void*)mctx->pc;
+#else
+        return (void*)mctx->gregs[REG_RIP];
+#endif
+#else
+        return (void*)mctx->gregs[REG_EIP];
+#endif
+#elif defined _darwin_
+#if defined _64_
+#if defined(_arm_)
+        return (void*)(*mctx)->__ss.__pc;
+#else
+        return (void*)(*mctx)->__ss.__rip;
+#endif
+#else
+#if defined(__IOS__)
+        return (void*)(*mctx)->__ss.__pc;
+#else
+        return (void*)(*mctx)->__ss.__eip;
+#endif
+#endif
+#endif
+    }
+
+    inline bool AddSample(void* key) {
+        ui32 slot = Hash(key);
+        ui32 prevSlot = (slot - 1) % SZ;
+
+        while (key != Ips[slot].first && !IsSlotEmpty(slot) && slot != prevSlot) {
+            slot = (slot + 1) % SZ;
+            SearchSkipCount++;
+        }
+
+        if (key == Ips[slot].first) {
+            // increment the count
+            Ips[slot].second++;
+            ++Samples;
+        } else if (InsertsAllowed()) {
+            // add new sample and set the count to 1
+            Ips[slot].first = key;
+            Ips[slot].second = 1;
+            ++UniqueSamples;
+            ++Samples;
+        } else {
+            // don't insert new sample if the search is becoming too slow
+            AtomicIncrement(DroppedSamples);
+            return false;
+        }
+
+        return true;
+    }
+
+    inline bool IsSlotEmpty(ui32 slot) const {
+        return Ips[slot].first == nullptr;
+    }
+
+    inline bool InsertsAllowed() const {
+        return UniqueSamples < SZ / 2;
+    }
+
+    void
+    Clear() {
+        Y_ASSERT(WriteFlag == 1);
+
+        for (size_t i = 0; i < SZ; ++i) {
+            Ips[i] = std::make_pair((void*)nullptr, (size_t)0);
+        }
+        Samples = 0;
+        AtomicSet(DroppedSamples, 0);
+        UniqueSamples = 0;
+        SearchSkipCount = 0;
+    }
+
+    bool Started;
+    struct sigaction OldSignalHandler;
+    itimerval OldTimerValue;
+
+    TVector<std::pair<void*, size_t>>
+        Ips; // The hash table storing addresses and their hitcounts
+
+    // TODO: on a big multiproc cache line false sharing by the flag and count might become an issue
+    TAtomic WriteFlag;      // Is used to syncronize access to the hash table
+    TAtomic DroppedSamples; // "dropped sample" count will show how many times
+                            // a sample was dropped either because of write conflict
+                            // or because of the hash table had become too filled up
+    ui64 Samples;           // Saved samples count
+    ui64 UniqueSamples;     // Number of unique addresses
+    ui64 SearchSkipCount;   // Total number of linear hash table probes due to collisions
+
+    static TExecutionSampler* SInstance;
+};
+
+// Performs analysis of samples captured by TExecutionSampler
+class TSampleAnalyser : TNonCopyable {
+public:
+    TSampleAnalyser(TExecutionSampler::TSampleVector& samples, const TExecutionSampler::TStats& stats, bool putTimeStamps = false)
+        : Samples()
+        , Stats(stats)
+        , PutTimestamps(putTimeStamps)
+    {
+        Samples.swap(samples);
+    }
+
+    ~TSampleAnalyser() = default;
+
+    void Analyze(FILE* out) const;
+
+private:
+    TExecutionSampler::TSampleVector Samples;
+    TExecutionSampler::TStats Stats;
+    bool PutTimestamps;
+};
+
+void TSampleAnalyser::Analyze(FILE* out) const {
+    fprintf(out, "samples: %" PRIu64 "    unique: %" PRIu64 "   dropped:  %" PRIu64 "   searchskips:   %" PRIu64 "\n",
+            (ui64)Stats.SavedSamples, (ui64)Samples.size(),
+            (ui64)Stats.DroppedSamples, (ui64)Stats.SearchSkipCount);
+
+    fprintf(out, "\nSamples:\n");
+    size_t funcCnt = 0;
+    void* prevModBase = (void*)-1;
+    void* prevFunc = (void*)-1;
+    for (size_t i = 0; i < Samples.size(); ++i) {
+        // print cycle count once in a while to estimate time consumed by
+        // dumping the samples
+        if (PutTimestamps && (i % 1000 == 0)) {
+            ui64 tm = GetCycleCount();
+            fprintf(out, "TM: %" PRIu64 "\n", tm);
+        }
+
+        Dl_info addrInfo;
+        if (dladdr(Samples[i].first, &addrInfo)) {
+            if (addrInfo.dli_fbase != prevModBase || addrInfo.dli_saddr != prevFunc) {
+                fprintf(out, "Func\t%" PRISZT "\t%p\t%p\t%s\t%s\n",
+                        funcCnt,
+                        addrInfo.dli_fbase,
+                        addrInfo.dli_saddr,
+                        addrInfo.dli_fname,
+                        addrInfo.dli_sname);
+                prevModBase = addrInfo.dli_fbase;
+                prevFunc = addrInfo.dli_saddr;
+                ++funcCnt;
+            }
+        } else {
+            fprintf(out, "[dladdr failed]\n");
+        }
+        fprintf(out, "%" PRISZT "\t%p\t%lu\n", i, Samples[i].first, Samples[i].second);
+    }
+}
+
+TExecutionSampler* TExecutionSampler::SInstance = nullptr;
+
+// Starts capturing execution samples
+void BeginProfiling() {
+    TExecutionSampler::Instance()->Start();
+}
+
+// Resets captured execution samples
+void ResetProfile() {
+    TExecutionSampler::Instance()->ResetStats();
+}
+
+void DumpRUsage(FILE* out) {
+    rusage ru;
+    int e = getrusage(RUSAGE_SELF, &ru);
+    if (e != 0)
+        return;
+
+    fprintf(out,
+            "user time:                       %lf\n"
+            "system time:                     %lf\n"
+            "max RSS:                         %ld\n"
+            "shared text:                     %ld\n"
+            "unshared data:                   %ld\n"
+            "unshared stack:                  %ld\n"
+            "page reclaims:                   %ld\n"
+            "page faults:                     %ld\n"
+            "swaps:                           %ld\n"
+            "block input ops:                 %ld\n"
+            "block output ops:                %ld\n"
+            "msg sent:                        %ld\n"
+            "msg received:                    %ld\n"
+            "signals:                         %ld\n"
+            "voluntary ctx switches:          %ld\n"
+            "involuntary ctx switches:        %ld\n\n",
+            ru.ru_utime.tv_sec + (ru.ru_utime.tv_usec * 0.000001),
+            ru.ru_stime.tv_sec + (ru.ru_stime.tv_usec * 0.000001),
+            ru.ru_maxrss, ru.ru_ixrss, ru.ru_idrss, ru.ru_isrss,
+            ru.ru_minflt, ru.ru_majflt, ru.ru_nswap,
+            ru.ru_inblock, ru.ru_oublock,
+            ru.ru_msgsnd, ru.ru_msgrcv,
+            ru.ru_nsignals,
+            ru.ru_nvcsw, ru.ru_nivcsw);
+}
+
+// Pauses capturing execution samples and dumps them to the file
+// Samples are not cleared so that profiling can be continued by calling BeginProfiling()
+// or it can be started from scratch by calling ResetProfile() and then BeginProfiling()
+void EndProfiling(FILE* out) {
+    DumpRUsage(out);
+
+    TExecutionSampler::TSampleVector samples;
+    TExecutionSampler::TStats stats;
+    TExecutionSampler::Instance()->Stop(samples, stats);
+
+    TSampleAnalyser analyzer(samples, stats);
+    analyzer.Analyze(out);
+}
+
+void EndProfiling() {
+    static unsigned cnt = 0;
+    char nameBuf[256];
+    snprintf(nameBuf, sizeof(nameBuf), "./%s.%d.%u.profile", getprogname(), (int)getpid(), cnt);
+    FILE* out = fopen(nameBuf, "a");
+    EndProfiling(out);
+    fclose(out);
+    ++cnt;
+}
+
+#else
+
+// NOTE: not supported on Windows
+
+void BeginProfiling() {
+}
+
+void ResetProfile() {
+}
+
+void EndProfiling(FILE*) {
+}
+
+void EndProfiling() {
+}
+
+#endif
diff --git a/library/cpp/execprofile/profile.h b/library/cpp/execprofile/profile.h
new file mode 100644
index 00000000000..ccb88666565
--- /dev/null
+++ b/library/cpp/execprofile/profile.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <stdio.h>
+
+// Starts capturing execution samples
+void BeginProfiling();
+
+// Resets captured execution samples
+void ResetProfile();
+
+// Pauses capturing execution samples and dumps them to the file
+// Samples are not cleared so that profiling can be continued by calling BeginProfiling()
+// or it can be started from scratch by calling ResetProfile() and then BeginProfiling()
+void EndProfiling(FILE* out);
+
+// Dumps the profile to default file (basename.pid.N.profile)
+void EndProfiling();
diff --git a/library/cpp/execprofile/ya.make b/library/cpp/execprofile/ya.make
new file mode 100644
index 00000000000..9d202ac4eb2
--- /dev/null
+++ b/library/cpp/execprofile/ya.make
@@ -0,0 +1,9 @@
+OWNER(g:cpp-contrib)
+
+LIBRARY()
+
+SRCS(
+    profile.cpp
+)
+
+END()