diff mbox series

[v10,3/6] nss: Add tests for the nss_hash in nss_hash.h

Message ID 20220518172635.291119-3-goldstein.w.n@gmail.com
State Superseded
Headers
Series [v10,1/6] elf: Refactor dl_new_hash so it can be tested / benchmarked |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Noah Goldstein May 18, 2022, 5:26 p.m. UTC 
  If we want to further optimize the function tests are needed.
---
 nss/Makefile          |  1 +
 nss/nss_hash.c        | 16 +++++++++
 nss/simple-nss-hash.h | 42 +++++++++++++++++++++++
 nss/tst-nss-hash.c    | 80 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 139 insertions(+)
 create mode 100644 nss/simple-nss-hash.h
 create mode 100644 nss/tst-nss-hash.c

Comments

Siddhesh Poyarekar May 19, 2022, 3:09 p.m. UTC | #1 
On 18/05/2022 22:56, Noah Goldstein via Libc-alpha wrote:
> If we want to further optimize the function tests are needed.
> ---
>   nss/Makefile          |  1 +
>   nss/nss_hash.c        | 16 +++++++++
>   nss/simple-nss-hash.h | 42 +++++++++++++++++++++++
>   nss/tst-nss-hash.c    | 80 +++++++++++++++++++++++++++++++++++++++++++
>   4 files changed, 139 insertions(+)
>   create mode 100644 nss/simple-nss-hash.h
>   create mode 100644 nss/tst-nss-hash.c

LGTM.

Reviewed-by: Siddhesh Poyarekar

> 
> diff --git a/nss/Makefile b/nss/Makefile
> index d8b06b44fb..a978e3927a 100644
> --- a/nss/Makefile
> +++ b/nss/Makefile
> @@ -62,6 +62,7 @@ tests := \
>     test-digits-dots \
>     test-netdb \
>     tst-nss-getpwent \
> +  tst-nss-hash \
>     tst-nss-test1 \
>     tst-nss-test2 \
>     tst-nss-test4 \
> diff --git a/nss/nss_hash.c b/nss/nss_hash.c
> index 27a348ea9b..f9e17d068a 100644
> --- a/nss/nss_hash.c
> +++ b/nss/nss_hash.c
> @@ -75,4 +75,20 @@ __nss_hash (const void *keyarg, size_t len)
>     return h;
>   }
>   
> +/* For testing/benchmarking purposes. */
> +static uint32_t
> +__simple_nss_hash (const void *keyarg, size_t len)
> +{
> +  const unsigned char *key;
> +  size_t i;
> +  uint32_t h = 0;
> +  key = keyarg;
> +
> +  for (i = 0; i < len; ++i)
> +    h = *key++ + 65599 * h;
> +
> +  return h;
> +}
> +
> +
>   libc_hidden_def (__nss_hash)
> diff --git a/nss/simple-nss-hash.h b/nss/simple-nss-hash.h
> new file mode 100644
> index 0000000000..47708972e7
> --- /dev/null
> +++ b/nss/simple-nss-hash.h
> @@ -0,0 +1,42 @@
> +/* __simple_nss_hash for testing nss_hash function
> +   Copyright (C) 2022 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#ifndef _SIMPLE_NSS_HASH_H
> +#define _SIMPLE_NSS_HASH_H 1
> +
> +#include <stdint.h>
> +
> +/* For testing/benchmarking purposes.  Real implementation in
> +   nss/nss_hash.c.  */
> +static uint32_t
> +__attribute__ ((unused))
> +__simple_nss_hash (const void *keyarg, size_t len)
> +{
> +  const unsigned char *key;
> +  size_t i;
> +  uint32_t h = 0;
> +  key = keyarg;
> +
> +  for (i = 0; i < len; ++i)
> +    h = *key++ + 65599 * h;
> +
> +  return h;
> +}
> +
> +
> +#endif /* simple-nss-hash.h */
> diff --git a/nss/tst-nss-hash.c b/nss/tst-nss-hash.c
> new file mode 100644
> index 0000000000..5ec1f9b0c5
> --- /dev/null
> +++ b/nss/tst-nss-hash.c
> @@ -0,0 +1,80 @@
> +/* Test __nss_hash
> +   Copyright (C) 2022 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <support/support.h>
> +#include <support/check.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdlib.h>
> +#include <nss.h>
> +#include <simple-nss-hash.h>
> +
> +uint32_t __nss_hash (const void *__key, size_t __length);
> +
> +static int
> +do_fill_tests (size_t len, int fill)
> +{
> +  uint32_t expec, res;
> +  char buf[len];
> +  memset (buf, fill, len);
> +
> +  expec = __simple_nss_hash (buf, len);
> +  res = __nss_hash (buf, len);
> +  if (expec != res)
> +    FAIL_EXIT1 ("FAIL: fill(%d) (%zu), %x != %x\n", fill, len, expec, res);
> +
> +  return 0;
> +}
> +
> +static int
> +do_rand_tests (size_t len)
> +{
> +  uint32_t expec, res;
> +  size_t i;
> +  char buf[len];
> +  for (i = 0; i < len; ++i)
> +    buf[i] = random ();
> +
> +  expec = __simple_nss_hash (buf, len);
> +  res = __nss_hash (buf, len);
> +  if (expec != res)
> +    FAIL_EXIT1 ("FAIL: random (%zu), %x != %x\n", len, expec, res);
> +
> +  return 0;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  size_t i, j;
> +  for (i = 0; i < 100; ++i)
> +    {
> +      for (j = 0; j < 8192; ++j)
> +	{
> +	  if (do_rand_tests (i))
> +	    return 1;
> +
> +	  if (do_fill_tests (i, -1) || do_fill_tests (i, 1)
> +	      || do_fill_tests (i, 0x80) || do_fill_tests (i, 0x88))
> +	    return 1;
> +	}
> +    }
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>
Siddhesh Poyarekar May 19, 2022, 3:40 p.m. UTC | #2 
On 19/05/2022 20:39, Siddhesh Poyarekar wrote:
> On 18/05/2022 22:56, Noah Goldstein via Libc-alpha wrote:
>> If we want to further optimize the function tests are needed.
>> ---
>>   nss/Makefile          |  1 +
>>   nss/nss_hash.c        | 16 +++++++++
>>   nss/simple-nss-hash.h | 42 +++++++++++++++++++++++
>>   nss/tst-nss-hash.c    | 80 +++++++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 139 insertions(+)
>>   create mode 100644 nss/simple-nss-hash.h
>>   create mode 100644 nss/tst-nss-hash.c
> 
> LGTM.
> 
> Reviewed-by: Siddhesh Poyarekar
> 
>>
>> diff --git a/nss/Makefile b/nss/Makefile
>> index d8b06b44fb..a978e3927a 100644
>> --- a/nss/Makefile
>> +++ b/nss/Makefile
>> @@ -62,6 +62,7 @@ tests := \
>>     test-digits-dots \
>>     test-netdb \
>>     tst-nss-getpwent \
>> +  tst-nss-hash \
>>     tst-nss-test1 \
>>     tst-nss-test2 \
>>     tst-nss-test4 \
>> diff --git a/nss/nss_hash.c b/nss/nss_hash.c
>> index 27a348ea9b..f9e17d068a 100644
>> --- a/nss/nss_hash.c
>> +++ b/nss/nss_hash.c
>> @@ -75,4 +75,20 @@ __nss_hash (const void *keyarg, size_t len)
>>     return h;
>>   }
>> +/* For testing/benchmarking purposes. */
>> +static uint32_t
>> +__simple_nss_hash (const void *keyarg, size_t len)
>> +{
>> +  const unsigned char *key;
>> +  size_t i;
>> +  uint32_t h = 0;
>> +  key = keyarg;
>> +
>> +  for (i = 0; i < len; ++i)
>> +    h = *key++ + 65599 * h;
>> +
>> +  return h;
>> +}
>> +
>> +

It just struck me (while reviewing 5/6) that this is duplicated in 
simple-nss-hash.h below.  Shouldn't it be one or the other?  I know it's 
"fixed" in 5/6 but it would be nice to restructure things so that the 
tree builds at this point of the patchset too.

>>   libc_hidden_def (__nss_hash)
>> diff --git a/nss/simple-nss-hash.h b/nss/simple-nss-hash.h
>> new file mode 100644
>> index 0000000000..47708972e7
>> --- /dev/null
>> +++ b/nss/simple-nss-hash.h
>> @@ -0,0 +1,42 @@
>> +/* __simple_nss_hash for testing nss_hash function
>> +   Copyright (C) 2022 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +   <https://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _SIMPLE_NSS_HASH_H
>> +#define _SIMPLE_NSS_HASH_H 1
>> +
>> +#include <stdint.h>
>> +
>> +/* For testing/benchmarking purposes.  Real implementation in
>> +   nss/nss_hash.c.  */
>> +static uint32_t
>> +__attribute__ ((unused))
>> +__simple_nss_hash (const void *keyarg, size_t len)
>> +{
>> +  const unsigned char *key;
>> +  size_t i;
>> +  uint32_t h = 0;
>> +  key = keyarg;
>> +
>> +  for (i = 0; i < len; ++i)
>> +    h = *key++ + 65599 * h;
>> +
>> +  return h;
>> +}
>> +
>> +
>> +#endif /* simple-nss-hash.h */
>> diff --git a/nss/tst-nss-hash.c b/nss/tst-nss-hash.c
>> new file mode 100644
>> index 0000000000..5ec1f9b0c5
>> --- /dev/null
>> +++ b/nss/tst-nss-hash.c
>> @@ -0,0 +1,80 @@
>> +/* Test __nss_hash
>> +   Copyright (C) 2022 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +   <https://www.gnu.org/licenses/>.  */
>> +
>> +#include <support/support.h>
>> +#include <support/check.h>
>> +#include <stdio.h>
>> +#include <string.h>
>> +#include <stdlib.h>
>> +#include <nss.h>
>> +#include <simple-nss-hash.h>
>> +
>> +uint32_t __nss_hash (const void *__key, size_t __length);
>> +
>> +static int
>> +do_fill_tests (size_t len, int fill)
>> +{
>> +  uint32_t expec, res;
>> +  char buf[len];
>> +  memset (buf, fill, len);
>> +
>> +  expec = __simple_nss_hash (buf, len);
>> +  res = __nss_hash (buf, len);
>> +  if (expec != res)
>> +    FAIL_EXIT1 ("FAIL: fill(%d) (%zu), %x != %x\n", fill, len, expec, 
>> res);
>> +
>> +  return 0;
>> +}
>> +
>> +static int
>> +do_rand_tests (size_t len)
>> +{
>> +  uint32_t expec, res;
>> +  size_t i;
>> +  char buf[len];
>> +  for (i = 0; i < len; ++i)
>> +    buf[i] = random ();
>> +
>> +  expec = __simple_nss_hash (buf, len);
>> +  res = __nss_hash (buf, len);
>> +  if (expec != res)
>> +    FAIL_EXIT1 ("FAIL: random (%zu), %x != %x\n", len, expec, res);
>> +
>> +  return 0;
>> +}
>> +
>> +static int
>> +do_test (void)
>> +{
>> +  size_t i, j;
>> +  for (i = 0; i < 100; ++i)
>> +    {
>> +      for (j = 0; j < 8192; ++j)
>> +    {
>> +      if (do_rand_tests (i))
>> +        return 1;
>> +
>> +      if (do_fill_tests (i, -1) || do_fill_tests (i, 1)
>> +          || do_fill_tests (i, 0x80) || do_fill_tests (i, 0x88))
>> +        return 1;
>> +    }
>> +    }
>> +  return 0;
>> +}
>> +
>> +#include <support/test-driver.c>
>
Noah Goldstein May 19, 2022, 10:20 p.m. UTC | #3 
On Thu, May 19, 2022 at 10:40 AM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
>
> On 19/05/2022 20:39, Siddhesh Poyarekar wrote:
> > On 18/05/2022 22:56, Noah Goldstein via Libc-alpha wrote:
> >> If we want to further optimize the function tests are needed.
> >> ---
> >>   nss/Makefile          |  1 +
> >>   nss/nss_hash.c        | 16 +++++++++
> >>   nss/simple-nss-hash.h | 42 +++++++++++++++++++++++
> >>   nss/tst-nss-hash.c    | 80 +++++++++++++++++++++++++++++++++++++++++++
> >>   4 files changed, 139 insertions(+)
> >>   create mode 100644 nss/simple-nss-hash.h
> >>   create mode 100644 nss/tst-nss-hash.c
> >
> > LGTM.
> >
> > Reviewed-by: Siddhesh Poyarekar
> >
> >>
> >> diff --git a/nss/Makefile b/nss/Makefile
> >> index d8b06b44fb..a978e3927a 100644
> >> --- a/nss/Makefile
> >> +++ b/nss/Makefile
> >> @@ -62,6 +62,7 @@ tests := \
> >>     test-digits-dots \
> >>     test-netdb \
> >>     tst-nss-getpwent \
> >> +  tst-nss-hash \
> >>     tst-nss-test1 \
> >>     tst-nss-test2 \
> >>     tst-nss-test4 \
> >> diff --git a/nss/nss_hash.c b/nss/nss_hash.c
> >> index 27a348ea9b..f9e17d068a 100644
> >> --- a/nss/nss_hash.c
> >> +++ b/nss/nss_hash.c
> >> @@ -75,4 +75,20 @@ __nss_hash (const void *keyarg, size_t len)
> >>     return h;
> >>   }
> >> +/* For testing/benchmarking purposes. */
> >> +static uint32_t
> >> +__simple_nss_hash (const void *keyarg, size_t len)
> >> +{
> >> +  const unsigned char *key;
> >> +  size_t i;
> >> +  uint32_t h = 0;
> >> +  key = keyarg;
> >> +
> >> +  for (i = 0; i < len; ++i)
> >> +    h = *key++ + 65599 * h;
> >> +
> >> +  return h;
> >> +}
> >> +
> >> +
>
> It just struck me (while reviewing 5/6) that this is duplicated in
> simple-nss-hash.h below.  Shouldn't it be one or the other?  I know it's
> "fixed" in 5/6 but it would be nice to restructure things so that the
> tree builds at this point of the patchset too.

Fixed V11. Forgot to fix in my last rebases :(
>
> >>   libc_hidden_def (__nss_hash)
> >> diff --git a/nss/simple-nss-hash.h b/nss/simple-nss-hash.h
> >> new file mode 100644
> >> index 0000000000..47708972e7
> >> --- /dev/null
> >> +++ b/nss/simple-nss-hash.h
> >> @@ -0,0 +1,42 @@
> >> +/* __simple_nss_hash for testing nss_hash function
> >> +   Copyright (C) 2022 Free Software Foundation, Inc.
> >> +   This file is part of the GNU C Library.
> >> +
> >> +   The GNU C Library is free software; you can redistribute it and/or
> >> +   modify it under the terms of the GNU Lesser General Public
> >> +   License as published by the Free Software Foundation; either
> >> +   version 2.1 of the License, or (at your option) any later version.
> >> +
> >> +   The GNU C Library is distributed in the hope that it will be useful,
> >> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> >> +   Lesser General Public License for more details.
> >> +
> >> +   You should have received a copy of the GNU Lesser General Public
> >> +   License along with the GNU C Library; if not, see
> >> +   <https://www.gnu.org/licenses/>.  */
> >> +
> >> +#ifndef _SIMPLE_NSS_HASH_H
> >> +#define _SIMPLE_NSS_HASH_H 1
> >> +
> >> +#include <stdint.h>
> >> +
> >> +/* For testing/benchmarking purposes.  Real implementation in
> >> +   nss/nss_hash.c.  */
> >> +static uint32_t
> >> +__attribute__ ((unused))
> >> +__simple_nss_hash (const void *keyarg, size_t len)
> >> +{
> >> +  const unsigned char *key;
> >> +  size_t i;
> >> +  uint32_t h = 0;
> >> +  key = keyarg;
> >> +
> >> +  for (i = 0; i < len; ++i)
> >> +    h = *key++ + 65599 * h;
> >> +
> >> +  return h;
> >> +}
> >> +
> >> +
> >> +#endif /* simple-nss-hash.h */
> >> diff --git a/nss/tst-nss-hash.c b/nss/tst-nss-hash.c
> >> new file mode 100644
> >> index 0000000000..5ec1f9b0c5
> >> --- /dev/null
> >> +++ b/nss/tst-nss-hash.c
> >> @@ -0,0 +1,80 @@
> >> +/* Test __nss_hash
> >> +   Copyright (C) 2022 Free Software Foundation, Inc.
> >> +   This file is part of the GNU C Library.
> >> +
> >> +   The GNU C Library is free software; you can redistribute it and/or
> >> +   modify it under the terms of the GNU Lesser General Public
> >> +   License as published by the Free Software Foundation; either
> >> +   version 2.1 of the License, or (at your option) any later version.
> >> +
> >> +   The GNU C Library is distributed in the hope that it will be useful,
> >> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> >> +   Lesser General Public License for more details.
> >> +
> >> +   You should have received a copy of the GNU Lesser General Public
> >> +   License along with the GNU C Library; if not, see
> >> +   <https://www.gnu.org/licenses/>.  */
> >> +
> >> +#include <support/support.h>
> >> +#include <support/check.h>
> >> +#include <stdio.h>
> >> +#include <string.h>
> >> +#include <stdlib.h>
> >> +#include <nss.h>
> >> +#include <simple-nss-hash.h>
> >> +
> >> +uint32_t __nss_hash (const void *__key, size_t __length);
> >> +
> >> +static int
> >> +do_fill_tests (size_t len, int fill)
> >> +{
> >> +  uint32_t expec, res;
> >> +  char buf[len];
> >> +  memset (buf, fill, len);
> >> +
> >> +  expec = __simple_nss_hash (buf, len);
> >> +  res = __nss_hash (buf, len);
> >> +  if (expec != res)
> >> +    FAIL_EXIT1 ("FAIL: fill(%d) (%zu), %x != %x\n", fill, len, expec,
> >> res);
> >> +
> >> +  return 0;
> >> +}
> >> +
> >> +static int
> >> +do_rand_tests (size_t len)
> >> +{
> >> +  uint32_t expec, res;
> >> +  size_t i;
> >> +  char buf[len];
> >> +  for (i = 0; i < len; ++i)
> >> +    buf[i] = random ();
> >> +
> >> +  expec = __simple_nss_hash (buf, len);
> >> +  res = __nss_hash (buf, len);
> >> +  if (expec != res)
> >> +    FAIL_EXIT1 ("FAIL: random (%zu), %x != %x\n", len, expec, res);
> >> +
> >> +  return 0;
> >> +}
> >> +
> >> +static int
> >> +do_test (void)
> >> +{
> >> +  size_t i, j;
> >> +  for (i = 0; i < 100; ++i)
> >> +    {
> >> +      for (j = 0; j < 8192; ++j)
> >> +    {
> >> +      if (do_rand_tests (i))
> >> +        return 1;
> >> +
> >> +      if (do_fill_tests (i, -1) || do_fill_tests (i, 1)
> >> +          || do_fill_tests (i, 0x80) || do_fill_tests (i, 0x88))
> >> +        return 1;
> >> +    }
> >> +    }
> >> +  return 0;
> >> +}
> >> +
> >> +#include <support/test-driver.c>
> >
>
diff mbox series

Patch

diff --git a/nss/Makefile b/nss/Makefile
index d8b06b44fb..a978e3927a 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -62,6 +62,7 @@  tests := \
   test-digits-dots \
   test-netdb \
   tst-nss-getpwent \
+  tst-nss-hash \
   tst-nss-test1 \
   tst-nss-test2 \
   tst-nss-test4 \
diff --git a/nss/nss_hash.c b/nss/nss_hash.c
index 27a348ea9b..f9e17d068a 100644
--- a/nss/nss_hash.c
+++ b/nss/nss_hash.c
@@ -75,4 +75,20 @@  __nss_hash (const void *keyarg, size_t len)
   return h;
 }
 
+/* For testing/benchmarking purposes. */
+static uint32_t
+__simple_nss_hash (const void *keyarg, size_t len)
+{
+  const unsigned char *key;
+  size_t i;
+  uint32_t h = 0;
+  key = keyarg;
+
+  for (i = 0; i < len; ++i)
+    h = *key++ + 65599 * h;
+
+  return h;
+}
+
+
 libc_hidden_def (__nss_hash)
diff --git a/nss/simple-nss-hash.h b/nss/simple-nss-hash.h
new file mode 100644
index 0000000000..47708972e7
--- /dev/null
+++ b/nss/simple-nss-hash.h
@@ -0,0 +1,42 @@ 
+/* __simple_nss_hash for testing nss_hash function
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SIMPLE_NSS_HASH_H
+#define _SIMPLE_NSS_HASH_H 1
+
+#include <stdint.h>
+
+/* For testing/benchmarking purposes.  Real implementation in
+   nss/nss_hash.c.  */
+static uint32_t
+__attribute__ ((unused))
+__simple_nss_hash (const void *keyarg, size_t len)
+{
+  const unsigned char *key;
+  size_t i;
+  uint32_t h = 0;
+  key = keyarg;
+
+  for (i = 0; i < len; ++i)
+    h = *key++ + 65599 * h;
+
+  return h;
+}
+
+
+#endif /* simple-nss-hash.h */
diff --git a/nss/tst-nss-hash.c b/nss/tst-nss-hash.c
new file mode 100644
index 0000000000..5ec1f9b0c5
--- /dev/null
+++ b/nss/tst-nss-hash.c
@@ -0,0 +1,80 @@ 
+/* Test __nss_hash
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/support.h>
+#include <support/check.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <nss.h>
+#include <simple-nss-hash.h>
+
+uint32_t __nss_hash (const void *__key, size_t __length);
+
+static int
+do_fill_tests (size_t len, int fill)
+{
+  uint32_t expec, res;
+  char buf[len];
+  memset (buf, fill, len);
+
+  expec = __simple_nss_hash (buf, len);
+  res = __nss_hash (buf, len);
+  if (expec != res)
+    FAIL_EXIT1 ("FAIL: fill(%d) (%zu), %x != %x\n", fill, len, expec, res);
+
+  return 0;
+}
+
+static int
+do_rand_tests (size_t len)
+{
+  uint32_t expec, res;
+  size_t i;
+  char buf[len];
+  for (i = 0; i < len; ++i)
+    buf[i] = random ();
+
+  expec = __simple_nss_hash (buf, len);
+  res = __nss_hash (buf, len);
+  if (expec != res)
+    FAIL_EXIT1 ("FAIL: random (%zu), %x != %x\n", len, expec, res);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  size_t i, j;
+  for (i = 0; i < 100; ++i)
+    {
+      for (j = 0; j < 8192; ++j)
+	{
+	  if (do_rand_tests (i))
+	    return 1;
+
+	  if (do_fill_tests (i, -1) || do_fill_tests (i, 1)
+	      || do_fill_tests (i, 0x80) || do_fill_tests (i, 0x88))
+	    return 1;
+	}
+    }
+  return 0;
+}
+
+#include <support/test-driver.c>