redict/tests/unit/replybufsize.tcl

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2024-03-21 09:30:47 -04:00
# SPDX-FileCopyrightText: 2024 Redict Contributors
# SPDX-FileCopyrightText: 2024 Salvatore Sanfilippo <antirez at gmail dot com>
#
# SPDX-License-Identifier: BSD-3-Clause
# SPDX-License-Identifier: LGPL-3.0-only
2024-03-21 09:30:47 -04:00
introduce dynamic client reply buffer size - save memory on idle clients (#9822) Current implementation simple idle client which serves no traffic still use ~17Kb of memory. this is mainly due to a fixed size reply buffer currently set to 16kb. We have encountered some cases in which the server operates in a low memory environments. In such cases a user who wishes to create large connection pools to support potential burst period, will exhaust a large amount of memory to maintain connected Idle clients. Some users may choose to "sacrifice" performance in order to save memory. This commit introduce a dynamic mechanism to shrink and expend the client reply buffer based on periodic observed peak. the algorithm works as follows: 1. each time a client reply buffer has been fully written, the last recorded peak is updated: new peak = MAX( last peak, current written size) 2. during clients cron we check for each client if the last observed peak was: a. matching the current buffer size - in which case we expend (resize) the buffer size by 100% b. less than half the buffer size - in which case we shrink the buffer size by 50% 3. In any case we will **not** resize the buffer in case: a. the current buffer peak is less then the current buffer usable size and higher than 1/2 the current buffer usable size b. the value of (current buffer usable size/2) is less than 1Kib c. the value of (current buffer usable size*2) is larger than 16Kib 4. the peak value is reset to the current buffer position once every **5** seconds. we maintain a new field in the client structure (buf_peak_last_reset_time) which is used to keep track of how long it passed since the last buffer peak reset. ### **Interface changes:** **CIENT LIST** - now contains 2 new extra fields: rbs= < the current size in bytes of the client reply buffer > rbp=< the current value in bytes of the last observed buffer peak position > **INFO STATS** - now contains 2 new statistics: reply_buffer_shrinks = < total number of buffer shrinks performed > reply_buffer_expends = < total number of buffer expends performed > Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Yoav Steinberg <yoav@redislabs.com>
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proc get_reply_buffer_size {cname} {
set clients [split [string trim [r client list]] "\r\n"]
set c [lsearch -inline $clients *name=$cname*]
if {![regexp rbs=(\[a-zA-Z0-9-\]+) $c - rbufsize]} {
error "field rbs not found in $c"
introduce dynamic client reply buffer size - save memory on idle clients (#9822) Current implementation simple idle client which serves no traffic still use ~17Kb of memory. this is mainly due to a fixed size reply buffer currently set to 16kb. We have encountered some cases in which the server operates in a low memory environments. In such cases a user who wishes to create large connection pools to support potential burst period, will exhaust a large amount of memory to maintain connected Idle clients. Some users may choose to "sacrifice" performance in order to save memory. This commit introduce a dynamic mechanism to shrink and expend the client reply buffer based on periodic observed peak. the algorithm works as follows: 1. each time a client reply buffer has been fully written, the last recorded peak is updated: new peak = MAX( last peak, current written size) 2. during clients cron we check for each client if the last observed peak was: a. matching the current buffer size - in which case we expend (resize) the buffer size by 100% b. less than half the buffer size - in which case we shrink the buffer size by 50% 3. In any case we will **not** resize the buffer in case: a. the current buffer peak is less then the current buffer usable size and higher than 1/2 the current buffer usable size b. the value of (current buffer usable size/2) is less than 1Kib c. the value of (current buffer usable size*2) is larger than 16Kib 4. the peak value is reset to the current buffer position once every **5** seconds. we maintain a new field in the client structure (buf_peak_last_reset_time) which is used to keep track of how long it passed since the last buffer peak reset. ### **Interface changes:** **CIENT LIST** - now contains 2 new extra fields: rbs= < the current size in bytes of the client reply buffer > rbp=< the current value in bytes of the last observed buffer peak position > **INFO STATS** - now contains 2 new statistics: reply_buffer_shrinks = < total number of buffer shrinks performed > reply_buffer_expends = < total number of buffer expends performed > Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Yoav Steinberg <yoav@redislabs.com>
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}
return $rbufsize
}
start_server {tags {"replybufsize"}} {
test {verify reply buffer limits} {
# In order to reduce test time we can set the peak reset time very low
r debug replybuffer peak-reset-time 100
introduce dynamic client reply buffer size - save memory on idle clients (#9822) Current implementation simple idle client which serves no traffic still use ~17Kb of memory. this is mainly due to a fixed size reply buffer currently set to 16kb. We have encountered some cases in which the server operates in a low memory environments. In such cases a user who wishes to create large connection pools to support potential burst period, will exhaust a large amount of memory to maintain connected Idle clients. Some users may choose to "sacrifice" performance in order to save memory. This commit introduce a dynamic mechanism to shrink and expend the client reply buffer based on periodic observed peak. the algorithm works as follows: 1. each time a client reply buffer has been fully written, the last recorded peak is updated: new peak = MAX( last peak, current written size) 2. during clients cron we check for each client if the last observed peak was: a. matching the current buffer size - in which case we expend (resize) the buffer size by 100% b. less than half the buffer size - in which case we shrink the buffer size by 50% 3. In any case we will **not** resize the buffer in case: a. the current buffer peak is less then the current buffer usable size and higher than 1/2 the current buffer usable size b. the value of (current buffer usable size/2) is less than 1Kib c. the value of (current buffer usable size*2) is larger than 16Kib 4. the peak value is reset to the current buffer position once every **5** seconds. we maintain a new field in the client structure (buf_peak_last_reset_time) which is used to keep track of how long it passed since the last buffer peak reset. ### **Interface changes:** **CIENT LIST** - now contains 2 new extra fields: rbs= < the current size in bytes of the client reply buffer > rbp=< the current value in bytes of the last observed buffer peak position > **INFO STATS** - now contains 2 new statistics: reply_buffer_shrinks = < total number of buffer shrinks performed > reply_buffer_expends = < total number of buffer expends performed > Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Yoav Steinberg <yoav@redislabs.com>
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# Create a simple idle test client
variable tc [redict_client]
introduce dynamic client reply buffer size - save memory on idle clients (#9822) Current implementation simple idle client which serves no traffic still use ~17Kb of memory. this is mainly due to a fixed size reply buffer currently set to 16kb. We have encountered some cases in which the server operates in a low memory environments. In such cases a user who wishes to create large connection pools to support potential burst period, will exhaust a large amount of memory to maintain connected Idle clients. Some users may choose to "sacrifice" performance in order to save memory. This commit introduce a dynamic mechanism to shrink and expend the client reply buffer based on periodic observed peak. the algorithm works as follows: 1. each time a client reply buffer has been fully written, the last recorded peak is updated: new peak = MAX( last peak, current written size) 2. during clients cron we check for each client if the last observed peak was: a. matching the current buffer size - in which case we expend (resize) the buffer size by 100% b. less than half the buffer size - in which case we shrink the buffer size by 50% 3. In any case we will **not** resize the buffer in case: a. the current buffer peak is less then the current buffer usable size and higher than 1/2 the current buffer usable size b. the value of (current buffer usable size/2) is less than 1Kib c. the value of (current buffer usable size*2) is larger than 16Kib 4. the peak value is reset to the current buffer position once every **5** seconds. we maintain a new field in the client structure (buf_peak_last_reset_time) which is used to keep track of how long it passed since the last buffer peak reset. ### **Interface changes:** **CIENT LIST** - now contains 2 new extra fields: rbs= < the current size in bytes of the client reply buffer > rbp=< the current value in bytes of the last observed buffer peak position > **INFO STATS** - now contains 2 new statistics: reply_buffer_shrinks = < total number of buffer shrinks performed > reply_buffer_expends = < total number of buffer expends performed > Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Yoav Steinberg <yoav@redislabs.com>
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$tc client setname test_client
# make sure the client is idle for 1 seconds to make it shrink the reply buffer
wait_for_condition 10 100 {
[get_reply_buffer_size test_client] >= 1024 && [get_reply_buffer_size test_client] < 2046
} else {
set rbs [get_reply_buffer_size test_client]
fail "reply buffer of idle client is $rbs after 1 seconds"
}
r set bigval [string repeat x 32768]
# In order to reduce test time we can set the peak reset time very low
r debug replybuffer peak-reset-time never
introduce dynamic client reply buffer size - save memory on idle clients (#9822) Current implementation simple idle client which serves no traffic still use ~17Kb of memory. this is mainly due to a fixed size reply buffer currently set to 16kb. We have encountered some cases in which the server operates in a low memory environments. In such cases a user who wishes to create large connection pools to support potential burst period, will exhaust a large amount of memory to maintain connected Idle clients. Some users may choose to "sacrifice" performance in order to save memory. This commit introduce a dynamic mechanism to shrink and expend the client reply buffer based on periodic observed peak. the algorithm works as follows: 1. each time a client reply buffer has been fully written, the last recorded peak is updated: new peak = MAX( last peak, current written size) 2. during clients cron we check for each client if the last observed peak was: a. matching the current buffer size - in which case we expend (resize) the buffer size by 100% b. less than half the buffer size - in which case we shrink the buffer size by 50% 3. In any case we will **not** resize the buffer in case: a. the current buffer peak is less then the current buffer usable size and higher than 1/2 the current buffer usable size b. the value of (current buffer usable size/2) is less than 1Kib c. the value of (current buffer usable size*2) is larger than 16Kib 4. the peak value is reset to the current buffer position once every **5** seconds. we maintain a new field in the client structure (buf_peak_last_reset_time) which is used to keep track of how long it passed since the last buffer peak reset. ### **Interface changes:** **CIENT LIST** - now contains 2 new extra fields: rbs= < the current size in bytes of the client reply buffer > rbp=< the current value in bytes of the last observed buffer peak position > **INFO STATS** - now contains 2 new statistics: reply_buffer_shrinks = < total number of buffer shrinks performed > reply_buffer_expends = < total number of buffer expends performed > Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Yoav Steinberg <yoav@redislabs.com>
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wait_for_condition 10 100 {
[$tc get bigval ; get_reply_buffer_size test_client] >= 16384 && [get_reply_buffer_size test_client] < 32768
} else {
set rbs [get_reply_buffer_size test_client]
fail "reply buffer of busy client is $rbs after 1 seconds"
}
# Restore the peak reset time to default
r debug replybuffer peak-reset-time reset
introduce dynamic client reply buffer size - save memory on idle clients (#9822) Current implementation simple idle client which serves no traffic still use ~17Kb of memory. this is mainly due to a fixed size reply buffer currently set to 16kb. We have encountered some cases in which the server operates in a low memory environments. In such cases a user who wishes to create large connection pools to support potential burst period, will exhaust a large amount of memory to maintain connected Idle clients. Some users may choose to "sacrifice" performance in order to save memory. This commit introduce a dynamic mechanism to shrink and expend the client reply buffer based on periodic observed peak. the algorithm works as follows: 1. each time a client reply buffer has been fully written, the last recorded peak is updated: new peak = MAX( last peak, current written size) 2. during clients cron we check for each client if the last observed peak was: a. matching the current buffer size - in which case we expend (resize) the buffer size by 100% b. less than half the buffer size - in which case we shrink the buffer size by 50% 3. In any case we will **not** resize the buffer in case: a. the current buffer peak is less then the current buffer usable size and higher than 1/2 the current buffer usable size b. the value of (current buffer usable size/2) is less than 1Kib c. the value of (current buffer usable size*2) is larger than 16Kib 4. the peak value is reset to the current buffer position once every **5** seconds. we maintain a new field in the client structure (buf_peak_last_reset_time) which is used to keep track of how long it passed since the last buffer peak reset. ### **Interface changes:** **CIENT LIST** - now contains 2 new extra fields: rbs= < the current size in bytes of the client reply buffer > rbp=< the current value in bytes of the last observed buffer peak position > **INFO STATS** - now contains 2 new statistics: reply_buffer_shrinks = < total number of buffer shrinks performed > reply_buffer_expends = < total number of buffer expends performed > Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Yoav Steinberg <yoav@redislabs.com>
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$tc close
} {0} {needs:debug}
}