<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">We are using a single SSL_CTX across all the threads, so I will create multiple SSL_CTX per thread. I implemented dynlock callbacks yesterday, but I didn’t see them being used in the tests I did. I also added atomic counters to see what type of locks are having contention (see logs below):<div class=""><br class=""></div><div class="">Most of the lock contention seems to be around type 2 and type 1 locks when calling our lock callback. In the FIPS/POST and SSL_CTX recommendations, in your previous email, what types of locks would those help with?</div><div class=""><br class=""></div><div class="">Log output:</div><div class=""><div style="margin: 0px;" class=""><font color="#931a68" face="Monaco" class=""><span style="font-size: 11px;" class="">[Apr 24 10:21:24.339] Server {0xb310000} ERROR: <<a href="http://SSLUtils.cc" class="">SSLUtils.cc</a>:178 (SSL_locking_callback)> contention for lock - total contention: 3938 waiting: 1 file: /SourceCache/OpenSSL098/OpenSSL098-52.20.2/src/crypto/ex_data.c line: 496 type: 2</span></font></div></div><div style="margin: 0px;" class=""><span style="font-size: 11px; color: rgb(147, 26, 104); font-family: Monaco;" class="">[Apr 24 10:21:24.754] Server {0xb10a000} ERROR: <<a href="http://SSLUtils.cc" class="">SSLUtils.cc</a>:178 (SSL_locking_callback)> contention for lock - total contention: 1350 waiting: 1 file: /SourceCache/OpenSSL098/OpenSSL098-52.20.2/src/crypto/err/err_def.c line: 343 type: 1</span></div><div style="margin: 0px;" class=""><br class=""></div><div style="margin: 0px;" class=""><font color="#931a68" face="Monaco" class=""><span style="font-size: 11px;" class=""><br class=""></span></font></div><div class=""><div class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">-Bryan</div><div class=""><br class=""></div></div><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
</div>
<br class=""><div class=""><blockquote type="cite" class=""><div class="">On Apr 23, 2015, at 4:46 PM, John Foley <<a href="mailto:foleyj@cisco.com" class="">foleyj@cisco.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" class="">
<div bgcolor="#FFFFFF" text="#000000" class="">
Looking at your call stack, it appears you're testing with FIPS mode
enabled. There's a lock in FIPS_selftest_failed() that's used to
ensure the crypto algorithms inside the FIPS boundary are not
utilized until after the POST has completed and passed.
Unfortunately this lock remains installed for the lifetime of the
process. We've seen thread contention in this area when using
OpenSSL. One work-around is to modify your handler that you pass to
SSL_locking_callback() to not lock when the lock ID is
CRYPTO_LOCK_FIPS. But you would only want to disable this
particular lock ID after the POST has completed.<br class="">
<br class="">
If the above doesn't help, another item to check is whether you're
instantiating an SSL_CTX for each thread. I've seen some developers
use a single SSL_CTX for multiple threads. This results in a single
instance of the server cert and private key being shared across all
the threads. This results in thread contention on the asymmetric
key operations associated with the cert and private key (e.g. RSA).
Be sure that each thread instantiates it's own SSL_CTX and
certificate/private key.<br class="">
<br class="">
Lastly, add some debugs to count the locks by lock ID in your lock
handler. There are about 40 different lock IDs defined in
crypto/crypto.h. You'll need to identify which lock is causing the
thread contention. Once you know that, then you can look in the
code to see where that lock is used and troubleshoot from there.<br class="">
<br class="">
<br class="">
<br class="">
<div class="moz-cite-prefix">On 04/23/2015 07:23 PM, Bryan Call
wrote:<br class="">
</div>
<blockquote cite="mid:20A62096-F3DE-4A11-8A76-CE081638E659@apache.org" type="cite" class="">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" class="">
I was running a benchmark on a 28 core (56 hyper-threaded) server
that is running 84 threads in the process and I am seeing a lot of
lock contention. I saw a lot of lock contention in the calls to
SSL_get_error() ssl3_accept(). I am running RHEL 6.5
and openssl-1.0.1e-30.el6_6.7.x86_64. We have
used SSL_locking_callback() to setup pthread mutex locks, but
haven’t setup dynlocks yet. Would dynlocks help in this scenario?
<div class=""><br class="">
</div>
<div class="">
<div class=""><br class="">
</div>
<div class="">Output from perf:</div>
<div class="">
<div class="">Samples: 1M of event 'cycles', Event count
(approx.): 602783506611</div>
<div class="">- 48.04% [ET_NET 0] [kernel.kallsyms] [k]
_spin_lock ◆</div>
<div class="">- _spin_lock ▒</div>
<ul class="">
<li class="">+ 48.05% futex_wait_setup ▒</li>
<li class="">+ 47.79% futex_wake ▒</li>
<li class="">+ 1.20% tcp_v4_rcv ▒</li>
<li class="">+ 0.98% task_rq_lock ▒</li>
<li class="">+ 0.64% double_lock_balance ▒</li>
</ul>
<div class="">+ 3.94% [ET_NET 0] libcrypto.so.1.0.1e [.]
bn_mul_mont ▒</div>
<div class="">+ 1.93% [ET_NET 0] libcrypto.so.1.0.1e [.]
BN_usub ▒</div>
<div class="">+ 1.80% [ET_NET 0] libcrypto.so.1.0.1e [.]
0x00000000000e5200 ▒</div>
<div class="">+ 1.49% [ET_NET 0] libcrypto.so.1.0.1e [.]
sha256_block_data_order ▒</div>
<div class="">+ 0.97% [ET_NET 0] libcrypto.so.1.0.1e [.]
gcm_ghash_clmul ▒</div>
<div class="">+ 0.85% [ET_NET 0] libpthread-2.12.so [.]
pthread_mutex_lock ▒</div>
<div class="">+ 0.84% [ET_NET 0] libcrypto.so.1.0.1e [.]
aesni_ctr32_encrypt_blocks ▒</div>
<div class="">+ 0.74% [ET_NET 0] libc-2.12.so [.] malloc ▒</div>
<div class="">+ 0.72% [ET_NET 0] libc-2.12.so [.] memcpy ▒</div>
<div class="">+ 0.57% [ET_NET 0] libcrypto.so.1.0.1e [.]
BN_mod_mul_montgomery ▒</div>
<div class="">+ 0.51% [ET_NET 0] libpthread-2.12.so [.]
pthread_mutex_unlock</div>
<div class=""><br class="webkit-block-placeholder">
</div>
<div class="">pstack of the process (only a couple of the
interesting threads):</div>
<div class="">
<div class=""><span style="font-family: 'Andale Mono';" class="">Thread 1 (Thread 0x7f1fba151800 (LWP 1106)):</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#0 0x00007f1fbaaeb264 in __lll_lock_wait ()
from /lib64/libpthread.so.0</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#1 0x00007f1fbaae6508 in _L_lock_854 () from
/lib64/libpthread.so.0</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#2 0x00007f1fbaae63d7 in pthread_mutex_lock ()
from /lib64/libpthread.so.0</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#3 0x000000000072822f in
SSL_locking_callback(int, int, char const*, int) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#4 0x00000031d2ae7f03 in ?? () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#5 0x00000031d2ae7d8c in ?? () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#6 0x00000031d2ae80ab in ERR_get_state () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#7 0x00000031d2ae8557 in ?? () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#8 0x00000031d2e424a9 in SSL_get_error () from
/usr/lib64/libssl.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#9 0x00000000007249ef in
SSLNetVConnection::load_buffer_and_write(long,
long&, long&, MIOBufferAccessor&, int&)
()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#10 0x00000000007389df in
write_to_net_io(NetHandler*, UnixNetVConnection*,
EThread*) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#11 0x0000000000738523 in
write_to_net(NetHandler*, UnixNetVConnection*, EThread*)
()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#12 0x0000000000731922 in
NetHandler::mainNetEvent(int, Event*) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#13 0x00000000004f6d48 in
Continuation::handleEvent(int, void*) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#14 0x000000000075877a in
EThread::process_event(Event*, int) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#15 0x0000000000758c84 in EThread::ex</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class=""><br class="">
</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">Thread 56 (Thread 0x7f1fb0ecd700 (LWP 1172)):</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#0 0x00007f1fbaae77d9 in pthread_mutex_unlock
() from /lib64/libpthread.so.0</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#1 0x0000000000728265 in
SSL_locking_callback(int, int, char const*, int) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#2 0x00000031d2b57402 in ?? () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#3 0x00000031d2b574bd in FIPS_selftest_failed
() from /usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#4 0x00000031d2ae9f1c in EVP_DigestInit_ex ()
from /usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#5 0x00000031d2a7977e in HMAC_Init_ex () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#6 0x00000031d2a79c29 in ?? () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#7 0x00000031d2af7a42 in EVP_PKEY_CTX_ctrl ()
from /usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#8 0x00000031d2ae9ffb in EVP_DigestInit_ex ()
from /usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#9 0x00000031d2af952a in ?? () from
/usr/lib64/libcrypto.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#10 0x00000031d2e34cf2 in tls1_PRF () from
/usr/lib64/libssl.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#11 0x00000031d2e35796 in tls1_final_finish_mac
() from /usr/lib64/libssl.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#12 0x00000031d2e2db2e in ssl3_get_message ()
from /usr/lib64/libssl.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#13 0x00000031d2e1dc3c in ssl3_get_cert_verify
() from /usr/lib64/libssl.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#14 0x00000031d2e220d6 in ssl3_accept () from
/usr/lib64/libssl.so.10</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#15 0x0000000000725287 in
SSLNetVConnection::sslServerHandShakeEvent(int&) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#16 0x00000000007251b3 in
SSLNetVConnection::sslStartHandShake(int, int&) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#17 0x0000000000723df3 in
SSLNetVConnection::net_read_io(NetHandler*, EThread*) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#18 0x0000000000731852 in
NetHandler::mainNetEvent(int, Event*) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#19 0x00000000004f6d48 in
Continuation::handleEvent(int, void*) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#20 0x000000000075877a in
EThread::process_event(Event*, int) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#21 0x0000000000758c84 in EThread::execute() ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#22 0x0000000000757cf8 in
spawn_thread_internal(void*) ()</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#23 0x00007f1fbaae49d1 in start_thread () from
/lib64/libpthread.so.0</span></div>
<div class=""><span style="font-family: 'Andale Mono';" class="">#24 0x00000030ff0e88fd in clone () from
/lib64/libc.so.6</span></div>
</div>
<div class=""><br class="">
</div>
<div class="">
<div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">
<div class="">-Bryan</div>
<div class=""><br class="">
</div>
</div>
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