Adding upstream version 5:7.2.4.upstream/5%7.2.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 400 insertions, 0 deletions

diff --git a/utils/lru/README b/utils/lru/README
new file mode 100644
index 0000000..f043b29
--- /dev/null
+++ b/utils/lru/README
@@ -0,0 +1,19 @@
+The test-lru.rb program can be used in order to check the behavior of the
+Redis approximated LRU algorithm against the theoretical output of true
+LRU algorithm.
+
+In order to use the program you need to recompile Redis setting the define
+REDIS_LRU_CLOCK_RESOLUTION to 1, by editing the file server.h.
+This allows to execute the program in a fast way since the 1 ms resolution
+is enough for all the objects to have a different enough time stamp during
+the test.
+
+The program is executed like this:
+
+    ruby test-lru.rb /tmp/lru.html
+
+You can optionally specify a number of times to run, so that the program
+will output averages of different runs, by adding an additional argument.
+For instance in order to run the test 10 times use:
+
+    ruby test-lru.rb /tmp/lru.html 10
diff --git a/utils/lru/lfu-simulation.c b/utils/lru/lfu-simulation.c
new file mode 100644
index 0000000..60105e5
--- /dev/null
+++ b/utils/lru/lfu-simulation.c
@@ -0,0 +1,158 @@
+#include <stdio.h>
+#include <time.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+int decr_every = 1;
+int keyspace_size = 1000000;
+time_t switch_after = 30; /* Switch access pattern after N seconds. */
+
+struct entry {
+    /* Field that the LFU Redis implementation will have (we have
+     * 24 bits of total space in the object->lru field). */
+    uint8_t counter;    /* Logarithmic counter. */
+    uint16_t decrtime;  /* (Reduced precision) time of last decrement. */
+
+    /* Fields only useful for visualization. */
+    uint64_t hits;      /* Number of real accesses. */
+    time_t ctime;       /* Key creation time. */
+};
+
+#define to_16bit_minutes(x) ((x/60) & 65535)
+#define LFU_INIT_VAL 5
+
+/* Compute the difference in minutes between two 16 bit minutes times
+ * obtained with to_16bit_minutes(). Since they can wrap around if
+ * we detect the overflow we account for it as if the counter wrapped
+ * a single time. */
+uint16_t minutes_diff(uint16_t now, uint16_t prev) {
+    if (now >= prev) return now-prev;
+    return 65535-prev+now;
+}
+
+/* Increment a counter logarithmically: the greatest is its value, the
+ * less likely is that the counter is really incremented.
+ * The maximum value of the counter is saturated at 255. */
+uint8_t log_incr(uint8_t counter) {
+    if (counter == 255) return counter;
+    double r = (double)rand()/RAND_MAX;
+    double baseval = counter-LFU_INIT_VAL;
+    if (baseval < 0) baseval = 0;
+    double limit = 1.0/(baseval*10+1);
+    if (r < limit) counter++;
+    return counter;
+}
+
+/* Simulate an access to an entry. */
+void access_entry(struct entry *e) {
+    e->counter = log_incr(e->counter);
+    e->hits++;
+}
+
+/* Return the entry LFU value and as a side effect decrement the
+ * entry value if the decrement time was reached. */
+uint8_t scan_entry(struct entry *e) {
+    if (minutes_diff(to_16bit_minutes(time(NULL)),e->decrtime)
+        >= decr_every)
+    {
+        if (e->counter) {
+            if (e->counter > LFU_INIT_VAL*2) {
+                e->counter /= 2;
+            } else {
+                e->counter--;
+            }
+        }
+        e->decrtime = to_16bit_minutes(time(NULL));
+    }
+    return e->counter;
+}
+
+/* Print the entry info. */
+void show_entry(long pos, struct entry *e) {
+    char *tag = "normal       ";
+
+    if (pos >= 10 && pos <= 14) tag = "new no access";
+    if (pos >= 15 && pos <= 19) tag = "new accessed ";
+    if (pos >= keyspace_size -5) tag= "old no access";
+
+    printf("%ld] <%s> frequency:%d decrtime:%d [%lu hits | age:%ld sec]\n",
+        pos, tag, e->counter, e->decrtime, (unsigned long)e->hits,
+            time(NULL) - e->ctime);
+}
+
+int main(void) {
+    time_t start = time(NULL);
+    time_t new_entry_time = start;
+    time_t display_time = start;
+    struct entry *entries = malloc(sizeof(*entries)*keyspace_size);
+    long j;
+
+    /* Initialize. */
+    for (j = 0; j < keyspace_size; j++) {
+        entries[j].counter = LFU_INIT_VAL;
+        entries[j].decrtime = to_16bit_minutes(start);
+        entries[j].hits = 0;
+        entries[j].ctime = time(NULL);
+    }
+
+    while(1) {
+        time_t now = time(NULL);
+        long idx;
+
+        /* Scan N random entries (simulates the eviction under maxmemory). */
+        for (j = 0; j < 3; j++) {
+            scan_entry(entries+(rand()%keyspace_size));
+        }
+
+        /* Access a random entry: use a power-law access pattern up to
+         * 'switch_after' seconds. Then revert to flat access pattern. */
+        if (now-start < switch_after) {
+            /* Power law. */
+            idx = 1;
+            while((rand() % 21) != 0 && idx < keyspace_size) idx *= 2;
+            if (idx > keyspace_size) idx = keyspace_size;
+            idx = rand() % idx;
+        } else {
+            /* Flat. */
+            idx = rand() % keyspace_size;
+        }
+
+        /* Never access entries between position 10 and 14, so that
+         * we simulate what happens to new entries that are never
+         * accessed VS new entries which are accessed in positions
+         * 15-19.
+         *
+         * Also never access last 5 entry, so that we have keys which
+         * are never recreated (old), and never accessed. */
+        if ((idx < 10 || idx > 14) && (idx < keyspace_size-5))
+            access_entry(entries+idx);
+
+        /* Simulate the addition of new entries at positions between
+         * 10 and 19, a random one every 10 seconds. */
+        if (new_entry_time <= now) {
+            idx = 10+(rand()%10);
+            entries[idx].counter = LFU_INIT_VAL;
+            entries[idx].decrtime = to_16bit_minutes(time(NULL));
+            entries[idx].hits = 0;
+            entries[idx].ctime = time(NULL);
+            new_entry_time = now+10;
+        }
+
+        /* Show the first 20 entries and the last 20 entries. */
+        if (display_time != now) {
+            printf("=============================\n");
+            printf("Current minutes time: %d\n", (int)to_16bit_minutes(now));
+            printf("Access method: %s\n",
+                (now-start < switch_after) ? "power-law" : "flat");
+
+            for (j = 0; j < 20; j++)
+                show_entry(j,entries+j);
+
+            for (j = keyspace_size-20; j < keyspace_size; j++)
+                show_entry(j,entries+j);
+            display_time = now;
+        }
+    }
+    return 0;
+}
+
diff --git a/utils/lru/test-lru.rb b/utils/lru/test-lru.rb
new file mode 100644
index 0000000..d511e20
--- /dev/null
+++ b/utils/lru/test-lru.rb
@@ -0,0 +1,223 @@
+require 'rubygems'
+require 'redis'
+
+$runs = []; # Remember the error rate of each run for average purposes.
+$o = {};    # Options set parsing arguments
+
+def testit(filename)
+    r = Redis.new
+    r.config("SET","maxmemory","2000000")
+    if $o[:ttl]
+        r.config("SET","maxmemory-policy","volatile-ttl")
+    else
+        r.config("SET","maxmemory-policy","allkeys-lru")
+    end
+    r.config("SET","maxmemory-samples",5)
+    r.config("RESETSTAT")
+    r.flushall
+
+    html = ""
+    html << <<EOF
+    <html>
+    <body>
+    <style>
+    .box {
+        width:5px;
+        height:5px;
+        float:left;
+        margin: 1px;
+    }
+
+    .old {
+        border: 1px black solid;
+    }
+
+    .new {
+        border: 1px green solid;
+    }
+
+    .otherdb {
+        border: 1px red solid;
+    }
+
+    .ex {
+        background-color: #666;
+    }
+    </style>
+    <pre>
+EOF
+
+    # Fill the DB up to the first eviction.
+    oldsize = r.dbsize
+    id = 0
+    while true
+        id += 1
+        begin
+            r.set(id,"foo")
+        rescue
+            break
+        end
+        newsize = r.dbsize
+        break if newsize == oldsize # A key was evicted? Stop.
+        oldsize = newsize
+    end
+
+    inserted = r.dbsize
+    first_set_max_id = id
+    html << "#{r.dbsize} keys inserted.\n"
+
+    # Access keys sequentially, so that in theory the first part will be expired
+    # and the latter part will not, according to perfect LRU.
+
+    if $o[:ttl]
+        STDERR.puts "Set increasing expire value"
+        (1..first_set_max_id).each{|id|
+            r.expire(id,1000+id)
+            STDERR.print(".") if (id % 150) == 0
+        }
+    else
+        STDERR.puts "Access keys sequentially"
+        (1..first_set_max_id).each{|id|
+            r.get(id)
+            sleep 0.001
+            STDERR.print(".") if (id % 150) == 0
+        }
+    end
+    STDERR.puts
+
+    # Insert more 50% keys. We expect that the new keys will rarely be expired
+    # since their last access time is recent compared to the others.
+    #
+    # Note that we insert the first 100 keys of the new set into DB1 instead
+    # of DB0, so that we can try how cross-DB eviction works.
+    half = inserted/2
+    html << "Insert enough keys to evict half the keys we inserted.\n"
+    add = 0
+
+    otherdb_start_idx = id+1
+    otherdb_end_idx = id+100
+    while true
+        add += 1
+        id += 1
+        if id >= otherdb_start_idx && id <= otherdb_end_idx
+            r.select(1)
+            r.set(id,"foo")
+            r.select(0)
+        else
+            r.set(id,"foo")
+        end
+        break if r.info['evicted_keys'].to_i >= half
+    end
+
+    html << "#{add} additional keys added.\n"
+    html << "#{r.dbsize} keys in DB.\n"
+
+    # Check if evicted keys respect LRU
+    # We consider errors from 1 to N progressively more serious as they violate
+    # more the access pattern.
+
+    errors = 0
+    e = 1
+    error_per_key = 100000.0/first_set_max_id
+    half_set_size = first_set_max_id/2
+    maxerr = 0
+    (1..(first_set_max_id/2)).each{|id|
+        if id >= otherdb_start_idx && id <= otherdb_end_idx
+            r.select(1)
+            exists = r.exists(id)
+            r.select(0)
+        else
+            exists = r.exists(id)
+        end
+        if id < first_set_max_id/2
+            thiserr = error_per_key * ((half_set_size-id).to_f/half_set_size)
+            maxerr += thiserr
+            errors += thiserr if exists
+        elsif id >= first_set_max_id/2
+            thiserr = error_per_key * ((id-half_set_size).to_f/half_set_size)
+            maxerr += thiserr
+            errors += thiserr if !exists
+        end
+    }
+    errors = errors*100/maxerr
+
+    STDERR.puts "Test finished with #{errors}% error! Generating HTML on stdout."
+
+    html << "#{errors}% error!\n"
+    html << "</pre>"
+    $runs << errors
+
+    # Generate the graphical representation
+    (1..id).each{|id|
+        # Mark first set and added items in a different way.
+        c = "box"
+        if id >= otherdb_start_idx && id <= otherdb_end_idx
+            c << " otherdb"
+        elsif id <= first_set_max_id
+            c << " old"
+        else
+            c << " new"
+        end
+
+        # Add class if exists
+        if id >= otherdb_start_idx && id <= otherdb_end_idx
+            r.select(1)
+            exists = r.exists(id)
+            r.select(0)
+        else
+            exists = r.exists(id)
+        end
+
+        c << " ex" if exists
+        html << "<div title=\"#{id}\" class=\"#{c}\"></div>"
+    }
+
+    # Close HTML page
+
+    html << <<EOF
+    </body>
+    </html>
+EOF
+
+    f = File.open(filename,"w")
+    f.write(html)
+    f.close
+end
+
+def print_avg
+    avg = ($runs.reduce {|a,b| a+b}) / $runs.length
+    puts "#{$runs.length} runs, AVG is #{avg}"
+end
+
+if ARGV.length < 1
+    STDERR.puts "Usage: ruby test-lru.rb <html-output-filename> [--runs <count>] [--ttl]"
+    STDERR.puts "Options:"
+    STDERR.puts "  --runs <count>    Execute the test <count> times."
+    STDERR.puts "  --ttl             Set keys with increasing TTL values"
+    STDERR.puts "                    (starting from 1000 seconds) in order to"
+    STDERR.puts "                    test the volatile-lru policy."
+    exit 1
+end
+
+filename = ARGV[0]
+$o[:numruns] = 1
+
+# Options parsing
+i = 1
+while i < ARGV.length
+    if ARGV[i] == '--runs'
+        $o[:numruns] = ARGV[i+1].to_i
+        i+= 1
+    elsif ARGV[i] == '--ttl'
+        $o[:ttl] = true
+    else
+        STDERR.puts "Unknown option #{ARGV[i]}"
+        exit 1
+    end
+    i+= 1
+end
+
+$o[:numruns].times {
+    testit(filename)
+    print_avg if $o[:numruns] != 1
+}