使用 cryptodev 引擎和硬件加速器的 openssl 速度测试会导致虚假的计时结果

Question

我正在尝试为我的硬件进行加密性能测试，同时我正在使用 openssl 速度测试命令。

我执行的第一个测试没有启用硬件加速器：

$ openssl speed -evp aes-128-cbc -engine cryptodev
Doing aes-128-cbc for 3s on 16 size blocks: 4437806 aes-128-cbc's in 3.00s
Doing aes-128-cbc for 3s on 64 size blocks: 1244528 aes-128-cbc's in 3.00s
Doing aes-128-cbc for 3s on 256 size blocks: 322780 aes-128-cbc's in 3.00s
Doing aes-128-cbc for 3s on 1024 size blocks: 81429 aes-128-cbc's in 3.00s
Doing aes-128-cbc for 3s on 8192 size blocks: 10215 aes-128-cbc's in 3.00s

OpenSSL 1.0.1j 15 Oct 2014
built on: Thu Jul 23 18:58:46 CDT 2015
options:bn(64,32) rc4(ptr,char) des(idx,cisc,16,long) aes(partial) idea(int) blowfish(ptr)
compiler: arm-poky-linux-gnueabi-gcc  -march=armv7-a -mthumb-interwork -mfloat-abi=hard
-mfpu=neon -mtune=cortex-a9 --sysroot=... -fPIC -DOPENSSL_PIC -DOPENSSL_THREADS
-D_REENTRANT -DDSO_DLFCN -DHAVE_DLFCN_H -DL_ENDIAN   -DTERMIO  -O2 -pipe -g 
-feliminate-unused-debug-types -Wall -Wa,--noexecstack -DHAVE_CRYPTODEV -DUSE_CRYPTODEV_DIGESTS
-DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM
-DAES_ASM -DGHASH_ASM

The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
aes-128-cbc      23668.30k    26549.93k    27543.89k    27794.43k    27893.76k

然后我启用硬件加速器并得到以下结果：

$ openssl speed -evp aes-128-cbc -engine cryptodev
engine "cryptodev" set.
Doing aes-128-cbc for 3s on 16 size blocks: 39552 aes-128-cbc's in ***0.08s***
Doing aes-128-cbc for 3s on 64 size blocks: 37060 aes-128-cbc's in ***0.05s***
Doing aes-128-cbc for 3s on 256 size blocks: 32674 aes-128-cbc's in ***0.07s***
Doing aes-128-cbc for 3s on 1024 size blocks: 26101 aes-128-cbc's in ***0.06s***
Doing aes-128-cbc for 3s on 8192 size blocks: 8286 aes-128-cbc's in ***0.02s***

OpenSSL 1.0.1j 15 Oct 2014
built on: Thu Jul 23 18:58:46 CDT 2015
options:bn(64,32) rc4(ptr,char) des(idx,cisc,16,long) aes(partial) idea(int) blowfish(ptr)
compiler: arm-poky-linux-gnueabi-gcc  -march=armv7-a -mthumb-interwork -mfloat-abi=hard
-mfpu=neon -mtune=cortex-a9 --sysroot=.... -fPIC -DOPENSSL_PIC -DOPENSSL_THREADS
-D_REENTRANT -DDSO_DLFCN -DHAVE_DLFCN_H -DL_ENDIAN   -DTERMIO  -O2 -pipe -g 
-feliminate-unused-debug-types -Wall -Wa,--noexecstack -DHAVE_CRYPTODEV -DUSE_CRYPTODEV_DIGESTS
-DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM
-DAES_ASM -DGHASH_ASM

The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes

我的问题是，为什么测试运行会持续 10 毫秒，而测试应该针对每个块大小运行持续 3 秒。这是 OpenSSL 中的错误吗？

我查看了 OpenSSL 1.0.1j 版中的代码，发现了以下内容：

#ifndef OPENSSL_NO_AES
        if (doit[D_CBC_128_AES])
                {
                for (j=0; j<SIZE_NUM; j++)
                        {
                        print_message(names[D_CBC_128_AES],c[D_CBC_128_AES][j],lengths[j]);
                        Time_F(START);
                        for (count=0,run=1; COND(c[D_CBC_128_AES][j]); count++)
                                AES_cbc_encrypt(buf,buf,
                                        (unsigned long)lengths[j],&aes_ks1,
                                        iv,AES_ENCRYPT);
                        d=Time_F(STOP);
                        print_result(D_CBC_128_AES,j,count,d);
                        }
                }

这里Time_F定义如下：

static double Time_F(int s)
        {
        return app_tminterval(s,usertime);
        }
#endif

app_tminterval 定义为：

#else
#include <sys/time.h>
#include <sys/resource.h>

double app_tminterval(int stop,int usertime)
        {
        double          ret = 0;
        struct rusage   rus;
        struct timeval  now;
        static struct timeval tmstart;

        if (usertime)           getrusage(RUSAGE_SELF,&rus), now = rus.ru_utime;
        else                    gettimeofday(&now,NULL);

        if (stop==TM_START)     tmstart = now;
        else                    ret = ( (now.tv_sec+now.tv_usec*1e-6)
                                        - (tmstart.tv_sec+tmstart.tv_usec*1e-6) );

        return ret;
        }
#endif

在这里我很困惑应用程序间隔停止在小于10ms而实际测试没有硬件加速器运行s 3s.

谢谢

Answer 1

使用-elapsed 来衡量总时间。

Openssl 测量 cpu 时间，当您将算法卸载到硬件加速器时，它释放了 cpu 的使用。结果，openssl 不会计算大部分时间，因为它花费在 cpu.

之外

使用 cryptodev 引擎和硬件加速器的 openssl 速度测试会导致虚假的计时结果

openssl speed test using cryptodev engine along with hardware accelerator leads to spurious timing results

encryption

openssl

arm

hardware-acceleration

neon